What Does White House's Climate Change Report Say About Climate Change Urgency?

Global warming, better known as climate change, has been at the forefront of environmentalists' minds for quite a few years now. The premise is that the planet's overall temperature will rise to the point of causing significant weather changes, which will impact agriculture, migration, economy, and a host of other issues. During Thanksgiving weekend, the U.S. government quietly released its Fourth National Climate Assessment. Looking at the news reports covering this, it confirms the extent to which anthropogenic climate change will end up being problematic down the road. In his bellicose fashion, President Trump denied the findings. Even so, the major news is that a report from the Trump administration, an administration that hasn't exactly been open to increased environmental regulations.

When looking at the report, there are some dire predictions, and that is just looking through the summary findings of the report. The Midwest could lose 25 percent of its production capacity for corn and soybeans. Ocean acidification will limit access to seafood. Pollen seasons will intensify. More extreme weather will cause depression, anxiety, and suicidality. Poor air quality and higher temperatures will result in more premature deaths. Labor-hours will be lost, thereby reducing economic output. There are more adverse effects, but the point that the report is making is that climate change is man-made, and it will wreak havoc on the United States.

A Dose of Skepticism
I wouldn't be doing my job if I were not at least a tad skeptical of this report. A good amount of this skepticism comes from the report's projected changes in climate (see below). There are three scenarios: the higher scenario (RCP8.5), the lower scenario (RCP4.5), and the even lower scenario (RCP2.6). In two out of the three scenarios, the temperatures would not rise to the 2C˚ post-Industrial revolution, the temperature in which climate scientists worry about cataclysmic events.

To be fair, this chart alone does not state the projected probability that each scenario is to occur. The report tries to answer this question, but provides an ambiguous answer (Box 2.4). On the one hand, emissions from the late 1990s up to the early 2010s suggest the higher scenario. On the other hand, since 2014, economic growth has been less carbon-intensive, thereby suggesting the lower scenario. The preliminary data for 2017 suggest a trend towards the higher scenario, but what matters here is that even the report is not certain about which scenario will play out.

There is further reason to be skeptical of the higher scenario beyond the report's ambiguity. The higher scenario is that: a worst-case scenario (e.g., Riahi et al., 2011, van Vuuren et al., 2011). It assumes that population growth is going to be high, technology development is going to be stagnant at a rate below historical averages, there will be a massive increase in poverty (which would be a major reversal of what has happened since the Industrial Revolution), coal consumption will increase 900 percent, and that GDP growth will be slow. As the Institute of Energy Research points out in its analysis of the White House report, the RCP8.5 model injects more pessimism beyond a lack of government action. I have expressed skepticism about implementing policy based on worst-case scenarios before, and given the findings from a 2017 article in Science (Hsiang et al., 2017), I have to wonder (see below).

Conclusion
It is not simply the issues with the climate change modeling or using an extreme scenario as the sole basis for the analysis. It also goes beyond ignoring certain climatological trends, such as as tornado occurrences plateauing since 1954, a more longitudinal look at global temperatures, a lack of trend for droughts and wildfires, or Arctic and Antarctic sea ice fluctuations (see American Enterprise Institute analysis here for more). There is also an issue of providing an accurate cost-benefit analysis. The report gets into the cost of inaction (Chapter 29), but does not specify the costs of action. Providing a cost-benefit analysis means getting the cost and benefits of all options, not just some. I am not here to say we should do nothing because I have made the argument for a modest carbon tax, as well as investing in research and development to lower carbon emissions. At the same time, the climate change we implement should a) have costs that are lower than the cost of climate change itself, b) mitigate the negative effects of climate change on standard of living, and c) be based on realistic projections, not implausible ones. Anything less would be doing a disservice in the world of environmental policy.