PNNL

Abstract

Climate change research and assessment, including the most recent report from the Intergovernmental Panel on Climate Change (IPCC), paint an increasingly dire picture of our future: hundreds of thousands of deaths from heat waves and other climate-related causes, billions of people at risk of disease, steeply rising damages from floods, millions pushed into poverty, 20% of species going extinct, tipping points about to be bridged, parts of the world already approaching the threshold of a survivable climate.1–3 Statements in the press have echoed and in some cases magnified the theme: we are “sleepwalking to climate catastrophe” and facing a "system-wide climate emergency." It is no wonder that large segments of the population in high income countries believe that climate change could lead to the extinction of humankind and at a minimum, that the future will be worse than the present.6 But according to the very same studies that underlie this dire outlook, that assumption is wrong for many aspects of human well-being. These studies anticipate a future in which in most scenarios, even with climate change, humanity is better educated, better fed, longer lived, healthier, with less poverty and less conflict, continuing trends that have been underway for decades.7 Furthermore, these improvements apply not just to the global or country average, but – where such outcomes have been examined – to more vulnerable populations as well. How is this seeming contradiction possible? An important contributor is the practice in climate change research and assessment reports of focusing predominantly on the additional effect of climate change to future human well-being, which is mainly negative, without putting it in the context of the total effect that is also driven by many non-climate factors, many of them positive. For example, climate change clearly represents a threat to human health, but at the same time better sanitation, improving health care systems, and biomedical progress are expected to continue to improve it. As a result, even with climate change leading to hundreds of thousands of additional deaths, declines in mortality from other causes are expected to greatly outweigh the climate effect, leading to increases of 10-20 years in life expectancy this century even in those countries with the shortest life expectancies today. Climate change acts to slow down that improvement, not to reverse it. This is not to say that climate impacts are unimportant; they are, and we need to address them, especially those that affect the most vulnerable. We cannot blithely trade off higher climate-related mortality against lower mortality from other causes, particularly since these effects will be unevenly spread across the population. But the mismatch between the climate-centric view of a slide toward potential collapse and the larger picture of slowed improvements has many consequences. Basic misunderstandings of the climate change issue permeate public and some policy discussion; overly pessimistic outlooks may blunt climate action by making it seem hopeless; policy priorities may become distorted by not distinguishing conditions that are truly likely to worsen from those that may only improve less quickly; and we may undermine scientific credibility when outcomes in the near future don't match predominant expectations.