If, after four decades, scientists see less warming and lower emissions, isn’t that good news?
Through five previous U.N. assessment plus their predecessor, the 1979 Charney Report, the likely worst-case was a rise of 4.5 degrees Celsius. This came from averaging the result of inconsistent computer climate simulations about which the IPCC knew only one thing: They couldn’t all be right and perhaps none were.
Using real-world data, the new report now says the worst case is a 4-degree rise. More important, with much greater confidence than before, disastrous outcomes above 5 degrees are now found to be very unlikely.
In another departure, the U.N. panel now says the dire emissions scenario it promoted for two decades should be regarded as highly unlikely, with more plausible projections at least a third lower.
The report also notes, as the press never does, the full impact of these emissions won’t be manifested until decades, even a century, later. The ultimate likely worst-case effect of a doubling of CO2 might be 4 degrees, but the best estimate of the “transient climate response” this century is about 2.7 degrees, or 1.6 degrees on top of the warming experienced since the start of the industrial age.
Imagine the news industry was still able to discern news. If the latest in a 40-year succession of climate forecasts differs from its predecessors in finding temperature change and emissions not as bad as previously projected, this would qualify as news. That is, to a media not wedded to the senseless assumption that climate science can only produce a succession of ever more dire discoveries.
Our climate fluctuates under many influences, but one factor that overwhelms all others is the increase in human beings and their valuable property placed in the path of extreme weather, behavior encouraged by politicians. Even so, human preparedness has advanced faster than climate change or even human building propensities. As University of Colorado Boulder’s Roger Pielke Jr. has patiently pointed out, your odds of dying from extreme weather have been declining drastically all through the period of growing human climate impact.
This progress had been made, so far at least, without help from climate policy, unless you consider fracking, which has led to a decline in total U.S. emissions, to be climate policy. Since mankind demonstrably is not going to arrest climate change by banning fossil fuels, and quite likely would leave itself on balance worse off if it did, let this be your good-news story of the day.