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Krugman: “The Depravity of Climate-Change Denial”

I ended my last post by noting that if we are to avoid devastating the planet and ourselves through climate change, drastic action is needed immediately. If you ask me, that’s been clear for a long time, but the truth has been denied by climate change deniers. Climate change deniers dislike the word “denial” because it comes from the psychological mechanism of denial, like addicts who deny that they have an addiction.

Perhaps climate change deniers do have an illness like addiction, or perhaps it is something even worse.

In a recent OpEd, Paul Krugman compares the denial of climate change to the denial that cigarette smoking is harmful. According to him, tobacco companies knew for decades that smoking was harmful, but undertook a cynical campaign to try to discredit the science around smoking. Why? Money. They were willing to let hundreds of thousands die in order to preserve profits. The denial of climate change, he says, has been undertaken by fossil fuel companies for precisely the same reason, using precisely the same tactics (and, in fact, using some of the same organizations to conduct the campaign). He also gives a nod to mistrust of government regulation, which will be required to address climate change (while also poking fun at it, noting that their mistrust somehow manages to allow governments to force consumers to subsidize coal. Thus, the real motivation is reduced back to money.) Krugman concludes that this is not just misguided, it is depraved.

The amazing thing is that their nonsense has taken hold of an entire political party (the Republicans) and a great number of people in this state (Missouri). It reminds one of how Naziism took hold of a large number of people in Germany during the 1930s. We look back and ask how rational people could have believed such obvious nonsense, such vile evil? Could such things happen in the USA? Well, try reading The Paranoid Style in American Politics for a starter. Of course it could.

The climate change deniers I have known fall into two camps. Some are simple people who are just repeating what they have heard their neighbors say, or what they have seen in the conservative media they like to follow. Others are more informed. These deniers like to see themselves as skeptics, but to me they seem pervasively suspicious, oppositional, and perhaps even querulous. They are preoccupied with unjustifiable doubts, often seeing conspiracies where none exist. They focus on details or outright fabrications to prop up their denial, while ignoring vast amounts of fact, upon which they turn their back. Because not everything is known, they argue that nothing is known.

I received an email from one, a British lord no less, who comfortably turned his back on thousands of scientific references in an IPCC report, in favor of a column written by the host of an Australian children’s TV show. Well, he claimed, climate science is a vast conspiracy.

Is that paranoia? Has it gone so far as to be a psychotic delusion? Were the German people who supported Naziism deluded? Psychotic? At what point does fear of the future – I’m fearful, too, it would be silly not to be – turn into suspicion and paranoia?

Well, this IPCC report makes it clear that global warming, if left unchecked, is going to cost hundreds of billions of dollars yearly, and is going to ruin the lives of hundreds of millions. Clinging on to denial in the face of such facts, Krugman writes, is depraved. It is no longer a viable intellectual or political position, he argues, it is a sign of depravity.

Drastic change is required immediately if we are to avoid terrible damage to our planet. Even in only economic terms, the projected damage if we do nothing is absolutely staggering. But in addition to that, the lives of hundreds of millions will be ruined. Can humankind respond with the kind of immediate, large-scale planetary change that is required, or is it already too late? Will we act, or have we sold ourselves out to the forces of depravity?

Sources:

Hofstadter, Richard. 1996. The Paranoid Style in American Politics, and Other Essays. Cambridge, MA: Harvard University Press. Originally published in 1952.

Intergovernmental Panel on Climate Change. 2018. Global Warming of 1.5°C (Draft). Downloaded 11/24/2018 from https://www.ipcc.ch/report/sr15.

Krugman, Paul. “The Depravity of Climate-Change Denial.” The New York Times, November 26, 2018. Viewed online 12/1/2018 at https://www.nytimes.com/2018/11/26/opinion/climate-change-denial-republican.html.

Global Warming of 1.5°C (2)

In the previous post, I reported that the recent IPCC report, Global Warming of 1.5°C, concludes that it is theoretically possible to limit global warming to 1.5°C, but it would require drastic change: a 50% reduction in GHG emissions by 2030, and zero net GHG emissions by 2050. In this post, I will discuss some of what the report says about making such a change.

The IPCC reviewed a number of computer models to explore scenarios that limited global warming to 1.5°C. Assumptions varied between the models, and they consequently yielded different results. They can be grouped into several categories: models that projected an increase in Global Mean Surface Temperature (GMST) that stayed below 1.5°C, models that projected a small overshoot of 1.5°C (eventually returning to 1.5°C), models that projected a large overshoot of 1.5°C (eventually returning to 1.5°C), models that projected a 2.0°C increase in GMST, and models that projected a large increase above 2.0°C.

CO2 Emission Price

Figure 1. Source: Intergovernmental Panel on Climate Change, 2018.

According to the report, limiting the increase in GMST to 1.5°F would require putting a substantial price on carbon emissions. Estimates vary widely, thus, there is substantial uncertainty about just how large the price increase would need to be. It is clear, however, that the smaller the increase in GMST, the higher the price would have to be, and in all cases, the price would need to rise over time. Figure 1 shows the findings. The required price of carbon emissions is on the vertical axis, and the year is on the horizontal axis. The different colored columns represent the categories defined in the preceding paragraph.

The projected price for 2030 ranges from $135 to $5500 per metric ton of CO2e. The projected price in 2050 ranges from $245 to $13,000 per metric ton of CO2e. For comparison, at 11:22 a.m. CST on 12/4/18, Bloomberg reported the current price for emissions on the European Emissions Exchange was €20.72 ($23.48). Thus, the estimate for 2030 ranges from about 6 to 234 times the current price. I don’t know if fossil fuel prices would increase equally, but you can be sure they would increase a lot!

Carbon pricing, however, would not be sufficient in and of itself, and other policies would be required. The strategies mentioned in the report include using less energy, converting electricity generation to methods that don’t release carbon dioxide, converting all fuels to types that don’t release carbon dioxide, converting all energy end use to use decarbonized electricity (e.g. electric cars that run on renewable electricity), and some form of carbon sequestration. This is an intimidating list of changes. It would involve transforming basically all of our energy use infrastructure.

I couldn’t find an estimate of the cost of making the required transformation.

Threats to systems

Figure 2. Source: Intergovernmental Panel on Climate Change, 2018.

IPCC also doesn’t make specific predictions about the consequences of unchecked global warming, such as “Miami will flood,” or “400 million people will die of famine.” Rather, they speak of threats, how many people will be exposed to them, and which natural systems will be impacted. Figure 2 shows that for all of the systems considered, the threat increases the higher GMST goes. The increase in GMST is shown on the vertical axis. In the columns, white means the system will not impacted. Yellow means it will be impacted moderately. Red indicates that the impact will be severe and widespread. Purple indicates that the impacts will not only be severe, but perhaps irreversible, and also that the ability to cope with and adapt to the change will be limited. It is easy to see that for all systems, the risks increase as global warming increases. Some of the systems enter the red or purple color at or below 1.5C. But many of them only turn red or purple between 1.5 and 2.0°C.

The consequences are dramatic. The report discusses the specifics at great length, and they are far too numerous and complex to try to summarize here. However, I will say that the reports quotes estimates that, if no policy is instituted to limit global warming, GMST would rise 3.66°F by 2100, and it would reduce global Gross World Product (GWP) by 2.6%. According to the CIA World Factbook, GWP in 2017 was $127.8 trillion. Thus, even if GWP does not grow over time, a 2.6% reduction would equate to $3.3 trillion. In comparison, limiting global warming to 2°C would result in a decrease in GWP of 0.5% ($639 billion), and the 1.5°C scenario would result in a reduction of 0.3% ($383 billion).

Thus, the damage associated with global warming increases dramatically the more it warms. Limiting climate change to 1.5°C compared to 2.0°C would prevent $256 billion in economic loss every year. Thus, over a 10-year period, if you spent $2.5 trillion on climate change prevention, it would still be justifiable on the basis of avoided damage. A few trillion dollars here, hundreds of billions of dollars there – pretty soon, it will add up to real money!

The report includes population projections in its modeling of future climate change: increasing the population increases GHG emissions, and hence, it increases future climate change. The report does NOT address, however, limiting population as a strategy for limiting climate change, and least I could not find a section that did. Hmm! (If it’s there and I missed it, please let me know in a comment.)

The report is based on more than 6,000 scientific references. It contains a great deal of information, far too much to adequately summarize here. It should make clear, however, that the denial of climate change is no longer viable. If you ask me, it’s been clear for a long time, but this is pretty definitive.

Drastic change is required immediately if we are to avoid terrible damage to our planet. Even in only economic terms, the projected damage if we do nothing is absolutely staggering. Can humankind respond with the kind of immediate, large-scale planetary change that is required, or is it already too late?

Sources:

Bloomberg.com. Markets: Energy. Viewed online 12/4/2018 at https://www.bloomberg.com/energ.

Central Intelligence Agency. 2018. The World Factbook 2016-17. Viewed online 11/30/2018 at https://www.cia.gov/library/publications/the-world-factbook/index.html.

Intergovernmental Panel on Climate Change. 2018. Global Warming of 1.5°C (Draft). Downloaded 11/24/2018 from https://www.ipcc.ch/report/sr15.

Global Warming of 1.5°C (1)

Can we limit global warming to 1.5°C? What would it require? Would there be real advantages compared to letting earth’s climate warm more than that? These are the questions that the Intergovernmental Panel on Climate Change (IPCC) Special Report 15, Global Warming of 1.5°C seeks to answer. IPCC is, of course, discussing human-induced global warming, not natural climate change. I will discuss their answer to the first question in this post, and the other two questions in the next post.

Let’s start by understanding what we can expect from this report.

Figure 1 shows an image of something. It appears to be something white. It is too far away and out of focus to see more. Figure 2 moves a little closer. Now it is possible to see that that it is a white rectangle with some gray smudges on it.

Figure 3 moves a little closer. You can’t see the whole of the white rectangle, but the gray smudges can now be seen to be a word: “Titanic.” But the writing is still out of focus. Figure 4 moves a little closer still, and the writing is now in clear focus.

Over the years, the IPCC has issued a series of reports on global warming/climate change. Over that time, the basic understanding of global warming has not changed. But as we have gotten closer, it has come more clearly into focus, and it has become possible to make out details that we couldn’t see before. We still don’t have global warming in full focus; we’re not to Figure 4 yet. But it has become possible to ask specific questions and give answers that, while not yet fully specific and detailed, are getting there. So, Global Warming of 1.5°C doesn’t contain radical new understandings. Rather, it is more detailed, and that is useful.

By the way, I chose the word “Titanic” on purpose. That ship was not built to survive a catastrophic iceberg strike, substandard steel may have been used to construct her, and she didn’t have enough lifeboats for all of the passengers. The captain denied the risk and sailed through the night into an iceberg field. By the time the iceberg was spotted dead ahead in the middle of the night, it was too late to turn and too late to stop. By that point, nothing they could do could change their fate: the Titanic was going to hit that berg and sink, and thousands were going to die.

Did I really write that? That’s really catastrophic, apocalyptic even! According to the IPCC report, we are very, very close to being like the Titanic. It may already be too late, but perhaps if we try really, really hard, it isn’t. Read on.

GMST 1850-Present

Figure 5. Global Mean Surface Temperature 1850-Present. Source: IPCC 2018.

Human activity has already caused our planet’s global mean surface air temperature (GMST) to warm approximately 1°C (1.8°F) since pre-industrial times, according to the report. GMST is increasing by about 0.2°C (0.36°F) per decade. The rate of warming appears to be increasing. Figure 5 shows the temperature trend. The gray line shows the monthly temperatures in the datasets. The orange line shows the change forced by both humans and nature combined, while the yellow line shows the change forced by human activities alone (it is hard to see because it is embedded in the yellow band, look closely) .

GMST is an average across the globe. Some regions have warmed more than others. For instance, the temperature over land has increased more than the temperature over water; 40-60% of human population lives in regions that have already warmed 1.5°C (2.7°F) or more. Thus, a 1.5°C increase in GMST implies a larger than 1.5°C increase over land, with a smaller increase over the ocean.

Past emissions (through 2017) are probably not sufficient to cause GMST to increase more than 1.5°C. Therefore, warming limited to 1.5°C is theoretically possible if human emissions are immediately reduced. Two ways in which the 1.5°C limit could be achieved are discussed in the report. One reduces GHG emissions sufficiently quickly so that the 1.5°C limit is never exceeded. The other would allow a small overshoot of the limit, with temperature then being brought back within the limit by removing carbon dioxide from the atmosphere.

Reduction Pathways

Figure 6. GHG Emission Reduction Pathways. Source: IPCC 2018.

To limit the increase of GMST to 1.5°C with no overshoot would require GHG emissions of no more than 25-30 billion metric tons of CO2e per year in 2030 (compared to estimates that under business as usual they will be 50-58 billion metric tons per year). And GHG EMISSIONS WOULD NEED TO DECLINE TO NET ZERO BY 2050. That’s right – no net GHG emissions by 2050. Figure 6 shows the reductions over time in emissions of CO2, methane, black carbon (soot), and nitrous oxide consistent with a 1.5°C increase in GMST.

The no-net-emissions requirement could be met by two strategies: the first would involve reducing emissions themselves. Reducing emissions at this magnitude would require near-total transformations of our energy, transportation, and agricultural systems. The second would involve widely deploying carbon dioxide removal mechanisms. The only currently proven mechanism for removing carbon dioxide from the atmosphere is revegetation, especially reforestation. Attempts to add carbon capture and sequestration to power plants have not yet proven viable.

The limits agreed to in the Paris Climate Agreement are not sufficient to limit the increase in GMST to 1.5°C.

In the next post, I will look at what the report has to say about strategies to meet the limit, and what the costs and benefits might be.

Sources:

Intergovernmental Panel on Climate Change. 2018. Global Warming of 1.5°C (Draft). Downloaded 11/24/2018 from https://www.ipcc.ch/report/sr15.

Hurricane Climatology

Recent weeks have been very active for tropical storms. At one time in the Atlantic, there were 3 hurricanes (Florence, Helene, and Isaac) and 2 tropical storms (Gordon and Joyce). In the Eastern Pacific, August saw 4 tropical cyclones active at the same time (Hector, Kristy, John, and Lleana). and in September, Hurricane Hector and a new storm, Hurricane Olivia, impacted Hawaii. In the Western Pacific there have been 28 named storms. One of them, Super-Typhoon Mangkhut, caused extensive damage in the Philippenes.

Is this normal, or are tropical storms getting worse?

Tropical cyclones are rotating, organized storm systems that originate over tropical or subtropical waters. They have a center of low pressure around which they rotate that can develop into an “eye” if the storm is sufficiently intense and well organized. The thunderstorms tend to get organized into bands of thunderstorms that spiral out from the center. Even outside the thunderstorms, however, they have high sustained winds. In the Northern Hemisphere, they rotate counter-clockwise. In the Southern Hemisphere, they rotate clockwise.

Tropical cyclones are classified by the speed of their winds:

  • Tropical Depressions have maximum sustained winds of 38 mph or less.
  • Tropical Storms have maximum sustained winds of 39 to 73 mph.
  • Hurricanes have maximum sustained winds of 74 mph or higher. In the Western Pacific, hurricanes are called typhoons. In the Indian Ocean and Southern Pacific, they are called cyclones.
  • Major Hurricane have maximum sustained winds of 111 mph or higher.

Hurricanes are further classified according to the Saffir-Simpson Hurricane Wind Scale:

  • Category 1: winds 74-95 mph., capable of causing damage even to well-constructed wood frame homes.
  • Category 2: winds 96-110 mph., capable of causing damage to roofs and siding, blowing shallowly rooted trees over, and causing power loss.
  • Category 3 (major hurricane): winds 111-129 mph., capable of causing structural damage to even well-built homes, snapping or uprooting lots of trees, and causing power outages that last for days.
  • Category 4 (major hurricane): winds 130-156 mph., capable of causing catastrophic damage, ripping whole roofs off houses or blowing down walls. Regions impacted may be uninhabitable for weeks or months.
  • Category 5 (major hurricane): winds 157 mph. or higher, capable of destroying most houses, blowing down most trees, cutting off access to whole regions, and making whole regions uninhabitable for weeks or months.

Figure 1. Source: National Oceanographic and Atmospheric Administration

Tropical cyclones generally originate near the equator. Figure 1 shows the major regions where tropical cyclones tend to form, and their typical paths. I’m not sure what sends so many of them up the U.S. coast, rather than coming ashore. Perhaps it is the jet stream, or the Gulf Current, or the Mid-Atlantic High.

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Figure 2: Cyclone Formation by Time of Year. Source: National Oceanic and Atmospheric Admiinistration.

Figure 2 divides the year into 10-day intervals, and counts the number of tropical storms, hurricanes, and major hurricanes that form in the Atlantic Basin per 100 years during each interval. August and September are “hurricane season,” and the 10 days from September 10-19 are the peak. This chart would seem to indicate that during that interval, between 90 and 100 tropical storms originate every 100 years in the Atlantic Basin. That averages out to about 0.9-1.0 per year. Thus, it would appear that the last several weeks have been unusually active.

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Figure 3. Data source: National Oceanographic and Atmospheric Administration

Figure 3 shows the number of tropical storms, hurricanes, and major hurricanes that have formed in the Atlantic Basin annually since 1851. The blue area shows the number of tropical storms, the red area shows the number of hurricanes, and the green area shows the number of major hurricanes. To each series I have fitted a polynomial regression line.

First, the variation between years is large for all of the series. Second, there are more tropical storms than hurricanes, and more hurricanes than major hurricanes. Third, all three series show an increasing trend over time. There are more tropical storms than there used to be, more hurricanes, and more major hurricanes. HOWEVER, in viewing these trends, one must keep in mind that today we have weather satellites, air travel, and a good deal more shipping density across the Atlantic Ocean. It is quite possible that some storms went undetected or unmeasured in the past, but that is no longer the case. Thus, the observed change could easily be due to better observations, not a real increase in the number of storms. I don’t have the ability to make that correction, but The Fifth Assessment Report of the Intergovernmental Panel on Climate Change concluded that evidence for an increase in the number of tropical cyclones is not robust.

Figure 4. Data source: Wikipedia Contributors, 9/14/18.

As noted above, tropical cyclones can form in 8 basins around the world. One might ask which produces the most severe storms? Figure 4 shows the data. All of the basins have produced storms with sustained winds above 150, but the highest ever recorded was 215 mph. in Hurricane Patricia in the Eastern Pacific in 2015. In terms of lowest central pressure, the lowest ever recorded was in Typhoon Tip in the Western Pacific in 1979.

One might also ask which basin produces the most severe storms. Record keeping began in a different year in each basin, however, there appears to be a clear answer: the Western Pacific. Counting only storms with a minimum central pressure below 970 kPa, this basin has produced more than twice as many as any other basin.

Large cyclonic storms most often form in the tropics during hurricane season, but they don’t have to. For instance, the so-called “Perfect Storm” (they made a movie about it starring George Clooney) was a 1991 storm that formed in the Atlantic off the coast of Canada on October 29. It developed into a Category 1 hurricane, with a well defined eye, not dissipating until after November 2. Similarly, the remnants of Tropical Storm Rina (2017) travelled north across the Atlantic, crossed the British Isles, and crossed Central Europe. Entering the Mediterranean Sea, it re-strengthened into a tropical storm, now called Numa, which developed an eye and other characteristics typical of a hurricane. It’s strength peaked on November 18, with maximum sustained winds of 63 mph., not quite hurricane strength, but close.

Sources:

Hartmann, D.L., A.M.G. Klein Tank, M. Rusticucci, L.V. Alexander, S. Brönnimann, Y. Charabi, F.J. Dentener, E.J. Dlugokencky, D.R. Easterling, A. Kaplan, B.J. Soden, P.W. Thorne, M. Wild and P.M. Zhai, 2013: Observations: Atmosphere and Surface. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
NASA Space Place. 2018. How Do Hurricanes Form. Downloaded 9/18/2018 from https://spaceplace.nasa.gov/hurricanes/en.

National Oceanic and Atmospheric Administration. 2018. Tropical Cyclone Climatology. Viewed online 9/18/2018 at https://www.nhc.noaa.gov/climo.

Wikipedia contributors. (2018, July 21). Cyclone Numa. In Wikipedia, The Free Encyclopedia. Retrieved 19:26, September 18, 2018, from https://en.wikipedia.org/w/index.php?title=Cyclone_Numa&oldid=851259614

Wikipedia contributors. (2018, September 14). List of the most intense tropical cyclones. In Wikipedia, The Free Encyclopedia. Retrieved 22:23, September 18, 2018, from https://en.wikipedia.org/w/index.php?title=List_of_the_most_intense_tropical_cyclones&oldid=859553932.

Very Dry vs. Very Wet Months in the United States, 2018 Update


I’ve reported on drought in the American West many times in this blog. What about the country as a whole?


One way of looking at this question is by asking each month how much of the country has been very dry, and how much as been very wet? By very dry, I mean that the amount of precipitation for that month falls in the lowest 10% for that month in the historical record. By very wet, I mean that the amount of precipitation for that month falls in the highest 10% for that month.

The National Oceanic and Atmospheric Administration keeps this data. They measure the precipitation in every county in the country, and calculate what percent of the country was very dry, and what percent was very wet. They have data for every month going back to January of 1895.

Figure 1. Data source: National Centers for Environmental Information.

Figure 1 shows the monthly data for every month all the way back to January, 1895. Blue bars represent the percentage of the country that is very wet. Red bars represent the percentage that is very dry. (To keep the blue and red bars from obscuring each other, I multiplied the dry percentage by -1, thereby inverting it on the chart.) I dropped trend lines on both data series. As you can see, there is considerable variation from year-to-year. There is a slight trend – hardly noticeable – towards more very wet months and fewer very dry months. But it is small, and the yearly variation is much greater than the trend.

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Figure 2. Data source: National Centers for Environmental Information.

Figure 2 shows the same data, but it beings in January, 1994.. I constructed this chart to see whether the most recent 25 years look different than the record as a whole. Again, blue bars represent very wet months, and the red bars represent very dry ones. I dropped linear trend lines on both data series, as before. The yearly variation is again larger than the trends. There appears to be virtually no trend in the number of very dry months. There is a small trend towards increasing number of very wet months. It appears a bit larger than did the one for the whole time period, but even so, it is tiny compared to the yearly variation.

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Figure 3. Data source: National Centers for Environmental Information.

It’s a bit hard to read the two data series on opposite sides of the zero line, so I constructed Figure 3. For each month it shows the percentage of the country that was very dry minus the percentage that was very wet. By doing my subtraction that way, numbers above zero mean that more of the country was very dry than very wet, and numbers below zero mean that more of the country was very wet. I dropped a linear trend on the data (red), and I also dropped a 15-year moving average on it. The chart shows that, as we saw in Figure 1, there is a slight trend towards fewer very dry months and more very wet ones. The variation is much larger than the trend, whether one looks at the monthly data, or the yearly.

This data differs from other drought data I report. Those reports focus on the Palmer Drought Severity Index, an index intended to represent soil moisture. Soil can dry out because there is little overall precipitation, or because there are longer periods between precipitation events, or because the temperature is warmer. This data would tend to indicate that regions of the country with very little precipitation may be decreasing very slightly, very slowly. Regions with very much precipitation may be increasing. This trend would be consistent with consensus predictions regarding climate change, where overall precipitation is not expected to change, but the number of heavy precipitation events is expected to increase.

Source:

National Centers for Environmental Information, National Oceanographic and Atmospheric Administration. U.S. Percentage Areas (Very Warm/Cold, Very Wet/Dry). Downloaded 9/1/2018 from https://www.ncdc.noaa.gov/temp-and-precip/uspa.

Drought in American Southwest (Revised)

Revision: This is a revision of the post that appeared yesterday, 8/2/18. The Drought Monitor map issued 7/31/18 shows drought intensifying in Missouri, and extending to include most of the state. In this revision, I’ve replaced the map with the newer one, and I’ve revised the text to include the new information.

Drought has one again gripped the American West and Southwest. Unfortunately, the wet winter of 2017 turned out to be a one-year reprieve. Perhaps the coming winter will be wet again, but for now, the regions are once again dry – in some cases, as dry as they have ever been since record-keeping began.

Figure 1. Source: Riganti, 2018.

Figure 1 shows the U.S. Drought Monitor for July 17, 2018. This map shows the Palmer Drought Severity Index for the United States. White areas are not in drought, colored areas are, and the darker the color, the worse the drought. It is easy to see that an “exceptional drought” has gripped portions of the Southwest, centered on the Four Corners Area where Colorado, New Mexico, Arizona, and Utah meet. Though the drought is most severe there, it has gripped much of the entire western United States.

Drought is primarily about soil moisture. Without moisture in the soil, crops wither and drinking water sources dry up. It is not feasible, however, to directly measure soil moisture across the entire country. The Palmer Drought Severity Index computes an estimate of soil moisture using temperature and precipitation data, and is the primary measure of drought used by the National Oceanographic and Atmospheric Administration.

 

Figure 2. Source: National Oceanographic and Atmospheric Administration, 2018.

Figure 2 shows the PDSI in June for the Southwest Climate Region (Arizona, Colorado, New Mexico, and Utah) from 1895 to 2018. Green columns represent years when it was wetter than average in June, orange columns when it was dryer than average. It is easy to see that green columns cluster to the left of the chart, and orange ones cluster to the right. In fact, of the most recent 19 years, 16 have been drier than average. This year, June was the second driest in the record, virtually as dry as it has ever been since record keeping began. The blue line shows the trend: the PDSI has decreased -0.23 per decade on average.

Ever since I wrote an extended series of posts on drought in California in 2015, this blog has followed the drought situation there. Plentiful snow during the winter of 2017 brought welcome relief, but the winter of 2018 was a big disappointment. Precipitation was below average, and the snowpack peaked well below normal (see here).

Figure 3. Source: Riganti, 2018.

As Figure 3 shows, California has not escaped the drought gripping most of the West. The most extreme drought is in the southeastern corner of the state. That is where the Imperial Valley is located, a region that supplies us with many of our fruits and vegetables. The farms there are mostly irrigated with water from the Colorado River, so local drought there is not a terrible worry for us here in Missouri. More on the Colorado River below, however.

 

 

 

 

Figure 4. Source: National Oceanographic and Atmospheric Administration, 2018.

Figure 4 shows that the PDSI for the state as a whole for June 2018, indicates a severe drought, but not an extreme one. The trend over time is clearly downward, however, and the continued dryness represents a long-term threat to the state’s water supply.

 

 

 

 

 

Figure 5. Source: California Department of Water Resources, 2018.

As Figure 5 shows, California’s reservoirs are moving into deficit. They have been fuller than average for most of the time since the winter of 2017, but now three of the biggest and most important, Trinity Lake, Lake Shasta, and Lake Oroville, are below average for this date. In the chart, the yellow bars represent the maximum capacity of each reservoir, the blue bars the current level, and the red line the average for this date. Lake Oroville has not yet fully recovered from the near disaster in 2017 that caused managers to lower the lake level to prevent a collapse of the dam(see here).

 

 

 

 

 

 

 

Figure 6. Source: Lake Mead Water Database, 2018.

Readers who have been following this blog know that California, Arizona, Nevada, Utah, New Mexico, and even Mexico depend on water from the Colorado River, and that Lake Mead is the large reservoir that holds the water for all of those states. You also know that water withdrawals from Lake Mead have exceeded inputs for many years, and the level of water in the lake has been relentlessly dropping. One study went so far as to predict that Lake Mead had a 50% chance of going dry by 2021. (Barnett and Pierce, 2008. See here for a fuller discussion California’s water resources.) Figure 6 shows the level of the lake for the past 3 years. The green line shows 2016, the red line 2017, and the blue line the year-to-date in 2018. Notice that the chart begins October 1, which is the official start of the water year. The wet winter of 2017 replenished the lake a little bit, but you can see that the current drought is causing it to drop again. Lake Mead is only 38% full, and Lake Powell, the large reservoir upstream from Lake Mead, is only 51% full. These low levels do not represent an immediate existential threat, but if dry conditions persist, they will before too many years pass.

 

Figure 7. Source: National Oceanographic and Atmospheric Administration, 2018.

The most important source of Missouri’s water is the Missouri River (see here). As Figure 7 shows, precipitation in the Northern Rockies and Plains Climate Region was slightly above average for the first 6 months of 2018. Statistics for the reservoirs along the Missouri show that they are at or near maximum storage. In fact, since part of their mission is flood control, several of them are higher than desired for that purpose. (U.S. Army Corps of Engineers, 2018)

Going back to Figure 1, however, you can see that the drought over the West has expanded to include Missouri, and it is especially severe in the northwestern part of the state. In St. Joseph, for instance, July brought 1.10 inches of rain, compared to 5.19 inches in an average July. In addition, since January 1, St. Joseph experienced 326 more heating degree days than average, an increase of 43%. That translates, on average, to a daily increase 1.8°F. (I arrived at this number by dividing the excess in heating degree days by the number of days.) Drought is as much a result of increased temperature as it is of reduced precipitation. Even if precipitation remains constant, increased temperature causes the ground to dry out more quickly, intensifying drought.

Because the reservoirs along the Missouri are relatively full, this drought will impact agriculture more than it will impact drinking water, unless your drinking water comes from wells. Drought can impact the availability of ground water to seep into wells, especially if they are shallow.

Climate projections for Missouri do not project a large decrease in precipitation. They tend to project that precipitation will remain about the same, or possibly increase slightly. Temperature, however, will rise, leading to a potential increase in the frequency of damaging drought. The real concern, however, is that the drought in the American West might not be not a temporary weather phenomenon, but, instead, a permanent change in climate. Modelers predict that climate change will cause just such a change Could it be occurring already?

Sources:

Barnett, Tim, and David Pierce. 2008. “When Will Lake Mead Go Dry?” Water Resources Research, 44, W03201. Retrieved online at http://www.image.ucar.edu/idag/Papers/PapersIDAGsubtask2.4/Barnett1.pdf.

Lake Mead Water Database. 2018. Lake Mead Daily Water Levels, Last 3 Water Years. Downloaded 7/19/2018 from http://graphs.water-data.com/lakemead.

National Oceanographic and Atmospheric Administration. 2018. Climate-at-a-Glance. Data downloaded 2018-07-19 from https://www.ncdc.noaa.gov/cag.

Riganti, Curtis. 2018. U.S. Drought Monitor, July 17, 2018. National Drought Mitigation Center. Downloaded 7/19/2018 from http://droughtmonitor.unl.edu.

U.S. Army Corps of Engineers, Missouri River Basin Water management. 2018. Mainstem and Tributary Reservoir Bulletin, 7/18/2018. Viewed online 7/19/2018 at http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/MRBWM_Reservoir.pdf.

Drought in American West and Southwest

Drought has one again gripped the American West and Southwest. Unfortunately, the wet winter of 2017 turned out to be a one-year reprieve. Perhaps the coming winter will be wet again, but for now, the regions are once again dry – in some cases, as dry as they have ever been since record-keeping began.

Figure 1. Source: Riganti, 2018.

Figure 1 shows the U.S. Drought Monitor for July 17, 2018. This map shows the Palmer Drought Severity Index for the United States. White areas are not in drought, colored areas are, and the darker the color, the worse the drought. It is easy to see that an “exceptional drought” has gripped portions of the Southwest, centered on the Four Corners Area where Colorado, New Mexico, Arizona, and Utah meet. Though the drought is most severe there, it has gripped much of the entire western United States.

Drought is primarily about soil moisture. Without moisture in the soil, crops wither and drinking water sources dry up. It is not feasible, however, to directly measure soil moisture across the entire country. The Palmer Drought Severity Index computes an estimate of soil moisture using temperature and precipitation data, and is the primary measure of drought used by the National Oceanographic and Atmospheric Administration.

 

Figure 2. Source: National Oceanographic and Atmospheric Administration, 2018.

Figure 2 shows the PDSI in June for the Southwest Climate Region (Arizona, Colorado, New Mexico, and Utah) from 1895 to 2018. Green columns represent years when it was wetter than average in June, orange columns when it was dryer than average. It is easy to see that green columns cluster to the left of the chart, and orange ones cluster to the right. In fact, of the most recent 19 years, 16 have been drier than average. This year, June was the second driest in the record, virtually as dry as it has ever been since record keeping began. The blue line shows the trend: the PDSI has decreased -0.23 per decade on average.

Ever since I wrote an extended series of posts on drought in California in 2015, this blog has followed the drought situation there. Plentiful snow during the winter of 2017 brought welcome relief, but the winter of 2018 was a big disappointment. Precipitation was below average, and the snowpack peaked well below normal (see here).

Figure 3. Source: Riganti, 2018.

As Figure 3 shows, California has not escaped the drought gripping most of the West. The most extreme drought is in the southeastern corner of the state. That is where the Imperial Valley is located, a region that supplies us with many of our fruits and vegetables. The farms there are mostly irrigated with water from the Colorado River, so local drought there is not a terrible worry for us here in Missouri. More on the Colorado River below, however.

 

 

 

 

Figure 4. Source: National Oceanographic and Atmospheric Administration, 2018.

Figure 4 shows that the PDSI for the state as a whole for June 2018, indicates a severe drought, but not an extreme one. The trend over time is clearly downward, however, and the continued dryness represents a long-term threat to the state’s water supply.

 

 

 

 

 

Figure 5. Source: California Department of Water Resources, 2018.

As Figure 5 shows, California’s reservoirs are moving into deficit. They have been fuller than average for most of the time since the winter of 2017, but now three of the biggest and most important, Trinity Lake, Lake Shasta, and Lake Oroville, are below average for this date. In the chart, the yellow bars represent the maximum capacity of each reservoir, the blue bars the current level, and the red line the average for this date. Lake Oroville has not yet fully recovered from the near disaster in 2017 that caused managers to lower the lake level to prevent a collapse of the dam(see here).

 

 

 

 

 

 

 

Figure 6. Source: Lake Mead Water Database, 2018.

Readers who have been following this blog know that California, Arizona, Nevada, Utah, New Mexico, and even Mexico depend on water from the Colorado River, and that Lake Mead is the large reservoir that holds the water for all of those states. You also know that water withdrawals from Lake Mead have exceeded inputs for many years, and the level of water in the lake has been relentlessly dropping. One study went so far as to predict that Lake Mead had a 50% chance of going dry by 2021. (Barnett and Pierce, 2008. See here for a fuller discussion California’s water resources.) Figure 6 shows the level of the lake for the past 3 years. The green line shows 2016, the red line 2017, and the blue line the year-to-date in 2018. Notice that the chart begins October 1, which is the official start of the water year. The wet winter of 2017 replenished the lake a little bit, but you can see that the current drought is causing it to drop again. Lake Mead is only 38% full, and Lake Powell, the large reservoir upstream from Lake Mead, is only 51% full. These low levels do not represent an immediate existential threat, but if dry conditions persist, they will before too many years pass.

 

Figure 7. Source: National Oceanographic and Atmospheric Administration, 2018.

The situation is different for Missouri. The most important source of water in our state is the Missouri Rivers (see here). Going back to Figure 1 above, you can see that drought is not severely impacting most of the region drained by the Missouri. As Figure 7 shows, precipitation in the Northern Rockies and Plains Climate Region was slightly above average for the first 6 months of 2018. Statistics for the reservoirs along the Missouri show that they are at or near maximum storage. In fact, since part of their mission is flood control, several of them are higher than desired for that purpose. (U.S. Army Corps of Engineers, 2018)

The real concern is that the drought in the American West might not be not a temporary weather phenomenon, but, instead, a permanent change in climate. Modelers predict that climate change will cause just such a change, could it be occurring already?

Sources:

Barnett, Tim, and David Pierce. 2008. “When Will Lake Mead Go Dry?” Water Resources Research, 44, W03201. Retrieved online at http://www.image.ucar.edu/idag/Papers/PapersIDAGsubtask2.4/Barnett1.pdf.

Lake Mead Water Database. 2018. Lake Mead Daily Water Levels, Last 3 Water Years. Downloaded 7/19/2018 from http://graphs.water-data.com/lakemead.

National Oceanographic and Atmospheric Administration. 2018. Climate-at-a-Glance. Data downloaded 2018-07-19 from https://www.ncdc.noaa.gov/cag.

Riganti, Curtis. 2018. U.S. Drought Monitor, July 17, 2018. National Drought Mitigation Center. Downloaded 7/19/2018 from http://droughtmonitor.unl.edu.

U.S. Army Corps of Engineers, Missouri River Basin Water management. 2018. Mainstem and Tributary Reservoir Bulletin, 7/18/2018. Viewed online 7/19/2018 at http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/MRBWM_Reservoir.pdf.

The First Half of 2018 Was Hot, but Not Record-Breaking

Figure 1. Source: National Oceanographic and Atmospheric Administration, 2018.

The first half of the year was hot across the USA, but not record-breaking. So says data published by the National Oceanographic and Atmospheric Administration, on their Climate-At-A-Glance data portal.

Figure 1 shows the average temperature across the 48 contiguous states for the months January – June. Nationwide, the first half of 2018 was the 13th hottest on record. There is a lot of variation from year-to-year, but the data show 4 distinct periods: at the beginning of the 20th Century, the average temperature was lower. During the 1930s-1950s, it was higher. From the 1960 to about 1980, it was cooler again, but not as cool as at the turn of the century. Then, beginning about 1980, the temperature began an upward trend. This upward trend is larger than any other trend in the record, due to global warming.

For larger view, click on figure.

Figure 2. Source: National Oceanographic and Atmospheric Administration, 2018.

Figure 2 shows the average temperature in Missouri for the months January – June. The first half of 2018 was the 93rd hottest on record across Missouri (out of 124 years). If you look more closely, the data reveal that May and June have been extremely hot, but the average across the period is lowered by the fact that we had an extraordinarily cool April – the 2nd coolest on record.

 

 

 

 

 

 

Figure 3. Data source: Hayhoe et al., 2003; Weather Underground, 2018.

Since the end of April, it has been hot; we’ve had a long stretch of days with the temperature above 90. In Missouri, May – June were the hottest on record. If climate change projections are correct, however, it’s nothing compared to what’s coming by the end of the century. Climate modelers have projected that under the high emissions scenario (which we continue to follow), by the end of the century the average number of days each summer when the high temperature reached above 90°F will triple, from 36 to 105. There will be 43 days above 100, the predict. (See here.) To try to figure out what that meant, I put a 105-day stretch on a calendar, and discovered that it would stretch from mid-June through the final weeks of September. I’ve reproduced that calendar as Figure 3. Dates projected to be above 90 are in orange, dates projected to be above 100 are in red. For comparison, I’ve marked on it the days in 2018 when the temperature was actually above 90°F in yellow, and dates when the temperature topped out below 90 in white. Dates in black had not yet occurred when the graphic was created (7/15/18).

You can see that we have a long way to go to equal what is predicted for us by the end of the century.

In terms of precipitation, the first half of 2018 was very close to average across Missouri (Figure 4). Across the Contiguous USA, it was just a touch above average (Figure 5). However, the averages do not tell the full story. After suffering a severe multi-year drought, the American West experienced a wet winter in 2017, but dry conditions returned in 2018. More on this in the next post, but Figure 6 shows that a drought centered on the Four Corners Area has once again gripped much of the West.

Figure 4. Source: National Oceanographic and Atmospheric Administration, 2018.

Figure 5. Source: National Oceanographic and Atmospheric Administration, 2018.

 

 

 

 

 

 

 

 

Figure 6. Source: Riganti, 2018.

All-in-all, for the first half of the year, the temperature and precipitation pattern for Missouri and the Contiguous USA were consistent with climate change predictions contained in the reports of the Intergovernmental Panel on Climate Change and the U.S. Global Change Research Program. Not every year will be a record year, they predict, but the trend will be towards warmer temperatures. Changes in precipitation will vary by region. For Missouri the reports predict no change or a slight increase in the average annual amount of precipitation.

Extremely hot days are associated with a number of undesirable effects, including increased deaths from heat exhaustion, increased respiratory illness, and reduced productivity. For a fuller discussion, see here.

Sources:

Hayhoe, K, J VanDorn, V. Naik, and D. Wuebbles. 2009. “Climate Change in the Midwest: Projections of Future Temperature and Precipitation.” Technical Report on Midwest Climate Impacts for the Union of Concerned Scientists. Downloaded from http://www.ucsusa.org/global_warming/science_and_impacts/impacts/climate-change-midwest.html#.VvK-OD-UmfA.

National Oceanographic and Atmospheric Administration. 2018. Climate-at-a-Glance. Data downloaded 2018-07-19 from https://www.ncdc.noaa.gov/cag/national/time-series.

Riganti, Curtis. 2018. U.S. Drought Monitor, July 17, 2018. National Drought Mitigation Center. Downloaded 7/19/2018 from http://droughtmonitor.unl.edu.

Weather Underground. St. Louis Downtown, IL >> History >> Monthly. Downloaded 2018-07-19 from https://www.wunderground.com/history/monthly/us/il/cahokia/KCPS/date/2018-7?cm_ven=localwx_history.

Energy-Related Emissions Grew in 2017

Figure 1. Source: International Energy Agency, 2018.

Global energy-related carbon dioxide emissions grew by 1.4% in 2017, reaching a historic high of 32.5 billion metric tons, according to a recent report by the International Energy Agency. The increase occurred because of a 2.1% increase in the global amount of energy consumed. Figure 1 shows the trend on energy-related carbon dioxide emissions.

(Click on figure for larger view.)

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Figure 2. Source: International Energy Agency, 2018.

More than 40% of the increase in energy consumption was driven by China and India. (See Figure 2) The result was an almost 150 million metric ton increase in China’s carbon dioxide emissions from energy. India’s emissions are not broken out, but carbon dioxide emissions from the rest of developing Asia (ex-China) were approximately 125 million metric tons higher than in 2016 (amounts are not precise because they are read from a graph).

Some countries had lower carbon dioxide emissions. The biggest decline came from the USA, where emissions declined 25 million metric tons, or 0.5%. In Mexico, emissions dropped 4%, and in the United Kingdom they dropped 3.8%. Way to go Mexico and United Kingdom! Because those countries consume far less energy than does the USA, the raw number of metric tons reduced was less than in the USA, despite the percentage being higher.

Last December I published a post reporting that worldwide carbon dioxide emissions from energy had held constant for the three years ending in 2016. What happened?

Figure 3. Source: International Energy Agency, 2018.

Figure 3 shows the drivers of the change in carbon dioxide emissions. Energy intensity (in yellow) has decreased every year since 2011, meaning that it required less energy to produce a unit of economic output. The rate at which energy intensity improved seemed to grow until 2015, but the rate of improvement seems to have slowed since then. Carbon dioxide intensity also seems to have improved in many of the years (meaning that less carbon dioxide is released per unit of energy produced, most likely from cleaner fuel). On the other hand, economic growth has occurred in every year. It accelerated in 2017, and its effect overwhelmed the effects of the other two drivers.

Figure 4. Source: International Energy Agency, 2018.

Figure 4 shows the annual growth in energy consumption by fuel. The chart shows that from 2006-2015, there was an average increase in consumption of all types of energy except nuclear. In 2016, however, there was a significant reduction in demand for energy from burning coal. Readers of this blog know that represents an important achievement, as coal emits more carbon dioxide per unit of energy than do the other fuels. However, in 2017, that achievement reversed itself, and demand for energy from burning coal rose again.

In 2017, the largest increase in energy demand was met by burning natural gas. The second largest increase in energy demand was met by renewable energy.

Overall, the report is not good news. As readers of this blog know, to prevent the worst effects of climate change, greenhouse gas emissions need to peak, and then be significantly reduced. There is no sign that is occurring. To quote the report:

The IEA’s Sustainable Development Scenario charts a path towards meeting long-term climate goals. Under this scenario, global emissions need to peak soon and decline steeply to 2020; this decline will now need to be even greater given the increase in emissions in 2017. The share of low-carbon energy sources must increase by 1.1 percentage points every year, more than five-times the growth registered in 2017. In the power sector, specifically, generation from renewable sources must increase by an average 700 TWh annually in that scenario, an 80% increase compared to the 380 TWh increase registered in 2017. (International Energy Agency, 2018, p. 4)

Source
International Energy Agency. 2018. Global Energy & CO2 Status Report, 2017. Downloaded 4/18/2018 from https://www.iea.org/geco.

Second Lowest Arctic Sea Ice on Record

Figure 1. Source: National Snow & Ice Data Center.

Arctic sea ice apparently reached its annual maximum extent on March 17, 2018, and it was the second lowest in the record, according to a report from the National Snow and Ice Data Center.

Each summer the arctic warms, and as it does, the sea ice covering the Arctic Ocean melts, reaching an annual low-point in late summer. Then, each winter the arctic cools, the surface of the ocean freezes, and the area covered by sea ice expands. The sea ice reaches its maximum extent in late winter, this year on March 17.

The National Snow and Ice Data Center tracks the extent of the sea ice using satellite images, as shown in Figure 1. The map is a polar view, with the North Pole in the center, the sea ice in white, and the ocean in blue. The land forms are in gray, with North America at lower left, and Eurasia running from Spain at lower right to the Russian Far East at the top. The magenta line shows the 1981-2010 average extent of the ice for the month of March. It doesn’t look like much on the map, but the anomaly in 2018 amounts to 436,300 square miles less than average.

(Click on figure for larger view.)

Figure 2. Source: National Snow & Ice Data Center.

Figure 2 shows the trend in Arctic sea ice from 1979-2018. The declining trend is easy to see. (The y-axis does not extend to zero to better show the change.) The National Snow and Ice Data Center applied a linear regression trend line to the data (blue line), and the trend shows an average loss of 16,400 square miles per year.

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What about the annual minimum? That has been shrinking, too. Figure 3 shows the Arctic sea ice minimum in 1980, and Figure 4 shows it in 2012. The prevailing winds tend to blow the ice up against Greenland and the far northern islands of Canada, but you can see that in 1980 most of the sea, from the Canadian islands, to Greenland, to the Svalbard Islands, to Severnaya Zemla (anybody remember the Bond movie “GoldenEye?”), to the north of Far Eastern Russia, was covered by ice. In 2012, however, more than half of the Arctic Sea was ice-free, from north of the Svalbard Islands right around to the Canadian Islands. Even the famed Northwest Passage, a channel through the Canadian Islands, was open.

Figure 3. Minimum Extent of Arctic Sea Ice, 1980. Source: NASA Scientific Visualization Studio.

Figure 4. Minimum Extent of Arctic Sea Ice, 2012. Source: NASA Scientific Visualization Studio.

 

 

 

 

 

 

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Figure 5. Minimum Extent of Arctic Sea Ice, 1979-2017. Source: NASA Global Climate Change.

Figure 5 charts the trend in the annual minimum. At its low in 2012, it was less than half of what it was in 1980.

The volume of the polar ice cap also depends on how thick the ice is. Satellites can photograph the entire ice cap, but data on thickness come to us from on-site measurements at a limited number of points. I don’t have a chart to share with you, but the data seem to indicate that compared to the years 1958-1976, in 2003-2007 the thickness had declined about 50% to 64%, depending on where the measurement was taken. (This change is approximate, being read off of a graph by Kwok and Rothrock, 2009.)

Thus, the decline in the arctic ice cap is actually much larger than suggested by the change in its extent.

Why does arctic sea ice matter? First, Arctic sea ice does not form primarily from snowfall, as does the snowcap in the western United States. Arctic sea ice forms because the temperature is low enough to cause the surface of the water to freeze, just as the your local pond or lake freezes if it gets cold enough. Thus, declining Arctic sea ice is a sign that the Arctic is warming. The Arctic seems to be the part of the planet that is warming the most from climate change, and this is a clear and graphic sign of that change.

Oddly, the warming arctic is one reason for the bizarre weather we have had in Missouri this winter. As noted in a post on 1/22/2015, the warming arctic weakens the polar vortex, which allows arctic cold to escape and travel south, impacting us in Missouri. Figure 6 shows the anomaly in Arctic temperatures from December, 2017 through February, 2018, in C. While it was warm over the entire Arctic, as much as 7°C above average (12.6°F), it was 2-3°C cooler than average over North America (3.6-5.4°F).

Second, it matters because ice is white, but the ocean is blue. That means that sunlight hitting ice reflects back towards space, and is not absorbed. Being blue, however, the ocean absorbs the light, and converts the energy to heat. This reflective capacity is called “albedo,” and the albedo of ocean is less than that of ice. Thus, the ice is melting because of global warming, but then, the melting contributes to even more global warming through the change in albedo. People are fond of saying that the earth has buffering mechanisms that tend to inhibit large climate changes, and such mechanisms do exist, but not everywhere in all things. This is one example where the earth shows positive feedback that destabilizes the climate even further.

Melting Arctic ice is not a major factor in the rising sea level. The reason is that the ice is already in the water. When the ice in your glass of iced tea melts, it doesn’t make the glass overflow. In the same way, as this ice melts, it has only a small effect on sea level. On the other hand, the Greenland Ice Cap and the Antarctic Ice Cap are not already in the water, and as they melt, they do affect sea level.

One final word: the data above are not computer models of future events. They are the best data available of what has already been happening, and what is happening now. To deny the reality of climate change is like denying that a river will flood, even as its water already swirls around your knees.

Sources:

Kwok, R., and D./A. Rothrock. 2009. “Decline in Arctic Sea Ice Thickness from Submarine and ICESat Records: 1958-2008. Beophysical Research Letters 36:L15501. Cited in National Snow & Ice Data Center. State of the Cryosphere. Viewed online 4/12/2018 at http://nsidc.org/cryosphere/sotc/sea_ice.html.

NASA Global Climate Change. Arctic Sea Ice Minimum. Downloaded 4/12/18 from https://climate.nasa.gov/vital-signs/arctic-sea-ice.

NASA Scientific Visualization Studio. Annual Arsctic Sea Ice Minimum 1979-2015 with Area Graph. Downloaded 4/12/18 from https://svs.gsfc.nasa.gov/4435.

NASA Scientific Visualization Studio. Annual Arsctic Sea Ice Minimum 1979-2015 with Area Graph. Downloaded 4/12/18 from https://svs.gsfc.nasa.gov/4435.

National Snow & Ice Data Center. “2018 Winter Arctic Sea Ice: Bering Down. Arctic Sea Ice News & Analysis. 4/4/2018. Downloaded 4/12/2018 from http://nsidc.org/arcticseaicenews.