Two important climate stories have somehow evaded media attention. The first is that the authoritative International Energy Agency now recognizes that the high-emissions (and therefore high-warming) scenarios associated with future energy use are flat-out wrong, and the second is that global greening is fighting global warming.
The only real attention that has been paid to the IEA’s bombshell is from University of Colorado’s Roger Pielke, who notes that “thousands” of alarmist articles in the scientific literature now need major revisions (or retraction?). This is a problem because that literature forms the core of the most recent (2018) United States “National Assessment” of climate change effects, a sort of biblical resource for policymakers and the media.
In its revelation, the IEA relies heavily on a withering article by University of British Columbia’s Justin Ritchie in the journal Energy, showing that the United Nation’s future energy use scenarios generally employ what he calls a “return to coal hypothesis,” in which coal use expands dramatically to the year 2100. The high-end scenario used by the U.N.’s Intergovernmental Panel on Climate Change simply ignores the rapid fuel-switching that is occurring as hydrofractured natural gas displaces coal for electricity generation, especially in the U.S.
Yet, the panel’s future energy consumption model producing the greatest warming is based upon the primitive notion that oil will soon be depleted and there will be a massive switch to coal, as Ritchie notes.
In its 2019 “World Energy Outlook” report, the IEA issued an updated suite of emissions projections, which are much lower than almost every scenario in both the most recent (2013) Intergovernmental Panel on Climate Change report and the next one due out in 2021.
The 2013 report specifies a range of future emissions, but the scientific community pays undue attention only to the highest one. IEA says we are on an emissions path that will produce less than half of the high-end warming, around 2.5 degrees Celsius this century. Most people, myself included, think that a 5 degrees Celsius warming this century is surely likely to cause major problems next century, as the year 2100 is not a magic point in which warming suddenly stops.
But the 2.5 degree Celsius estimate is likely too high because it uses the default assumptions in the widely employed Model for the Assessment of Greenhouse-gas Induced Climate Change. One of these assumptions is that the “sensitivity” of global surface temperature (the amount of warming calculated for doubling atmospheric carbon dioxide) is 3 degrees Celsius. Recent analyses using satellite data or observations of temperature and radiation changes yield sensitivities about half of that, which means the actual increases this century are likely to be much lower than even the IEA’s projection.
Writing in Forbes, Pielke noted:
Because of this, Pielke notes that the next climate compendium “is at risk of already being obsolete” because it relies on grossly inflated emissions scenarios.
Pielke concluded with a bang:
But wait, there’s even more!
There’s been a spectacular greening of the earth’s land surface that is being observed from satellites over both forested and agricultural ecosystems. The changes have been observed worldwide, with the largest increases in vegetation in the biologically critical tropical rainforests. Zaichun Zhu of Peking University noted in 2016 that human activity is responsible for over 90% of this greening, with a whopping 70% being from the direct “fertilization” effect of increasing atmospheric concentrations of carbon dioxide.
But what does this mean to global surface temperature? Until the very recent publication of research by Chi Chen (formerly with Boston University, now with the Department of Energy), it was unclear whether greening the planet resulted in net warming or cooling.
Chen’s numbers work out to close to 0.06 degrees Celsius cooling (caused by greening) over the 15-year period of study (2000-2014). How much surface average temperatures actually changed in that period is subject to some debate because the temperature records themselves are in flux. For example, the widely accepted “pause” in warming that began around 2000 disappeared with a controversial 2015 adjustment of the data by our National Oceanic and Atmospheric Administration.
The outgoing presidential administration took heat for President Trump’s proposal to combat warming by planting more trees, but he was actually “following the science.” Coupled with the more realistic emissions scenarios, increased vegetation will produce some further reduction in heating, most likely resulting in a 21st-century warming around 1.5 degrees Celsius, something we can easily accommodate and an amount that some economic models indicate confers net benefits.
Patrick J. Michaels is a senior fellow in Energy and Environment at the Competitive Enterprise Institute, a free market public policy organization based in Washington, D.C.
