Last week, National Journal’s Energy Insiders blog hosted a discussion on the question: “Is Global Warming the Planet’s Biggest Problem?” The blog has been experiencing technical difficulties, and several posts, including mine, are invisible (though they still exist on some server somewhere). So I have decided to repost my contribution here.
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Is global warming the planet’s biggest problem? Not even close.
Globally, poverty is by far the leading cause of preventable disease and premature death, and will likely remain so for decades to come.
The World Health Organization is hardly a hotbed of climate skepticism. Nonetheless, climate change ranks near the bottom of the WHO’s list of global health risk factors, well behind ”mundane” problems like indoor air pollution, waterborne disease, and vitamin A deficiency, notes economist Indur Goklany. Global warming remains low in the ranking, Goklany finds, even if one accepts the UK Government’s climate impact assessments that informed the alarmist Stern Review.
Al Gore and many other influential people claim global warming is “a planetary emergency – a crisis that threatens the survival of civilization and the habitability of the Earth.”
That is correct, however, only if one or more of their favorite doomsday scenarios is credible. Let’s examine the evidence.
In the mid-2000s, Gore and other pundits warned that the Atlantic Meridional Overturning Circulation (AMOC) could collapse, plunging Europe into an ice age, with all manner of terrible repercussions for the global economy and international stability. The AMOC is the oceanic “conveyor belt” that pulls warm water up from the equator to Northern Europe. In this scenario, melt water from the Greenland ice sheet so decreases the salinity (density) of North Atlantic surface water that it no longer sinks fast enough to drive the AMOC. A Pentagon-commissioned study on abrupt climate change gave credibility to this warming-causes-cooling scare. Climate activists were jubilant: ‘Even the generals are worried!’
The scenario rests on two assumptions: (1) the AMOC is chiefly responsible for Europe’s comparatively mild winters; (2) global warming is melting enough Greenland ice to shut down the AMOC. The first assumption is dubious, the second is highly implausible.
Richard Seager of Columbia University’s Lamont-Doherty Earth Observatory and colleagues found that the chief factor making England 15-20°F warmer in January than comparable latitudes in North America is not maritime heat transport via the AMOC but the very different prevailing winds that blow across northeastern North America and Western Europe. During the winter, “South-westerlies bring warm maritime air into Europe and north-westerlies bring frigid continental air into north-eastern North America.” Thus, Europe should continue to enjoy mild winters even if global warming weakens the AMOC.
The bursting of giant ice dams in central Canada – relics of the preceding ice age – allowed massive glacial lakes to drain swiftly into the Atlantic, and those fresh water pulses may have triggered the Younger Dryas cooling of 12,800 years ago and Europe’s mini-ice age of 8,200 years ago.
But even if that is what happened, it has little relevance today. An estimated 9,500 cubic kilometers of fresh water surged into the Atlantic at about the time of the Younger Dryas, and more than 100,000 cubic kilometers about the time of the European mini-ice age. In contrast, the rate of fresh water infusion from Greenland today is a comparative trickle — an estimated 222 cubic kilometers per year. As climatologist Patrick Michaels quipped: “Note to all readers: today, there is no bigger-than-all-the-Great-Lakes-combined glacial melt-water lake in central Canada held back by an ice dam on the verge of collapse.”
Recent empirical research on this topic gives no cause for alarm. Zhang et al. (2011) found that the “anticipated slowdown” in the AMO “has not occurred yet, even though global temperatures have been significantly higher since the 1970s.” Similarly, the IPCC Summary for Policymakers states: “There is no observational evidence of a trend in the Atlantic Meridional Overturning Circulation (AMOC), based on the decade-long record of the complete AMOC and longer records of individual AMOC components” [SPM-5].
As for the future, the IPCC predicts that although “some decline in the AMOC” is “likely” by 2050, “It is very unlikely that the AMOC will undergo an abrupt transition or collapse in the 21st century for the scenarios considered” [SPM-17].
Another apocalyptic storyline that would make global warming the world’s biggest problem is runaway climate change. In this scenario, melting permafrost releases vast deposits of frozen methane from the sea floor and huge stores of CO2 from peat bogs. Those “positive feedbacks” cause more warming, which then releases more methane and CO2, and so on, raising global temperatures dangerously high. Recent research does not support such gloomy speculation.
Schultz (2011) found that even under the most extreme climatic scenario tested, permafrost thaw in the Siberian shelf will not exceed 10 meters in depth by 2100 or 50 meters by the turn of the next millennium, whereas the bulk of methane stores are trapped roughly 200 meters below the sea floor.
Kessler et al. (2011) found that microbes digested the methane released during the 2010 BP Deepwater Horizon oil spill, indicating that any warming-induced “large-scale releases of methane from hydrate in the deep ocean are likely to be met by a similarly rapid methanotrophic [methane-eating] response.”
Charman et al. (2012) examined “carbon accumulation” in Northern latitude peat lands over the past millennium. “Opposite to expectations,” the scientists found that in warm periods, peat lands become more bio-productive, leading to net increases in “long-term carbon accumulation.” Thus, the researchers opine, “the carbon sequestration rate could increase over many areas of northern peat lands” as the world warms.
Loisel and Yu (2013) examined 15 peat cores collected from south-central Alaska. The two scientists found that “the observed apparent carbon accumulate rates over the past 100 years were almost ten times greater than those over the past 4000 years.” They conclude: “these results are contrary to the widespread notion that higher temperature will increase peat decay and associated carbon dioxide release from peat lands to the atmosphere, contributing to the positive carbon cycle-climate feedback to global warming.”
The best known doomsday scenario is that of rapid ice-sheet disintegration and catastrophic sea-level rise. There’s way more fiction than science in this narrative, too.
King et al. (2010) found that the rate of Antarctic ice loss is not accelerating and translates to less than one inch of sea-level rise per century. Faezeh et al. (2013) found that Greenland’s four main outlet glaciers are projected to contribute 0.7 to 1.1 inches to sea-level rise by 2200 under a mid-range warming scenario of 2.8°C by 2100 and 1.1 to 1.9 inches under a high-end warming scenario 4.5°C by 2100. The contribution of the great ice sheets to 21st century sea-level rise is more likely to be measured in inches than in feet or meters.
That’s also what the IPCC concludes. It projects that “Changes in outflow from both ice sheets combined will likely make a [global mean sea-level rise] contribution in the range of 0.03 to 0.20 m [1.1 inches to 7.8 inches] by 2081−2100” [SPM-18].
We often hear that global warming has made severe floods, droughts, and even “super-storms” the “new normal.” If correct, that would make global warming a big problem. To date, however, natural variability and social factors such as building codes and human settlement patterns remain much more important determinants of weather-related risk. Here’s the big picture on extreme weather:
- There has been no long term trend in the strength or frequency of hurricanes, tornadoes, U.S. floods or drought.
- Heat waves are becoming more frequent, as one would expect in a warmer climate. But, paradoxically, the more common hot weather becomes, the more heat-related mortality declines. People adapt!
- There is no long-term trend in “normalized” extreme weather damages – losses adjusted for increases in wealth, population, and consumer price index.
- Natural variability was chiefly responsible for the four largest heat events of the past decade: the 2003 European heat wave, the 2010 Russian heat wave, the 2011 Texas drought, and the 2012 Midwest drought.
- Globally, mortality rates and aggregate mortality related to extreme weather have declined by 98% and 93%, respectively, since the 1920s.
The latest IPCC report basically dumps cold water on extreme weather alarm, as Colorado University Prof. Roger Pielke, Jr. points out. Consider these excerpts from Chapter 2 of the Working Group I report:
- “Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century … No robust trends in annual numbers of tropical storms, hurricanes and major hurricanes counts have been identified over the past 100 years in the North Atlantic basin”
- “In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale”
- “Based on updated studies, AR4 conclusions regarding global increasing trends in drought since the 1970s were probably overstated.”
If global warming is the world’s most hyped problem, global warming alarm may well be the world’s most underrated problem.
With energy demand in developing countries rapidly increasing, cutting global emissions 50% by 2050 is not possible with current and foreseeable technologies. Absent technological breakthroughs, the IPCC’s emission stabilization targets can be met only by restricting developing countries’ access to plentiful, affordable, fossil fuels. That would be a humanitarian disaster.
Even in industrialized nations, carbon taxes, carbon caps, and renewable electricity mandates can destroy jobs and income. An abundant literature confirms the widespread intuition that poverty and unemployment imperil life and health.
In the global warming debate, there has been far too little discussion of whether the proposed cure is worse than the alleged disease.