资源环境科技发展态势分析平台

At the time of this writing, the Category 4 Hurricane Laura recently made landfall near the Texas-Louisiana border, two days after Tropical Storm Marco blew through the same area. Simultaneously, wildfires are raging across the American West, burning over one million acres and threatening tens of thousands of homes and other structures in California alone. From coast to coast, the threat of flood and fire is a real and persistent source of fear for millions of Americans.

According to natural scientists, climate change is intensifying natural disasters like wildfires and floods, making them increasingly devastating. In its Fifth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) detailed current and projected impacts of anthropogenic activity on climate changes and extreme weather events. In the executive summary of its region-specific examinations of North America, the IPCC Working Group 2 stated:

"North America’s climate has changed and some societally relevant changes have been attributed to anthropogenic causes (very high confidence). Recent climate changes and individual extreme events demonstrate both impacts of climate related stresses and vulnerabilities of exposed systems (very high confidence)...Many climate stresses that carry risk—particularly related to severe heat, heavy precipitation, and declining snowpack—will increase in frequency and/or severity in North America in the next decades (very high confidence).

"Global warming of approximately 2°C (above the preindustrial baseline) is very likely to lead to more frequent extreme heat events and daily precipitation extremes over most areas of North America, more frequent low-snow years, and shifts toward earlier snowmelt runoff over much of the western USA and Canada. Together with climate hazards such as higher sea levels and associated storm surges, more intense droughts, and increased precipitation variability, these changes are projected to lead to increased stresses to water, agriculture, economic activities, and urban and rural settlements."

As the world warms, the cost to Americans may also justify local and national efforts to adapt to damage exacerbated by climate change. For example, the spread of fire can be limited by reducing the amount of burnable materials in forests, whether it be through controlled burns or mechanical thinning (Scott et al. 2012). Federal and state governments could expand firefighting personnel to increase capacity to effectively limit the spread of fires. In flood-prone areas, governments can discourage or prevent people from building houses or other structures. After fires or floods, governments can help victims to recover through financial assistance or recovery programs. The government can implement these efforts and more through the use of taxpayer dollars.

The majority of these proposed policies are considered “adaptation policies,” as they seek to change human behavior in response to climate change, instead of “mitigation policies” which would focus on curbing the effects of climate change itself. Although a few policies could be considered as mitigation—namely expanding firefighting personnel or removing dead vegetation—this report will use “adaptation policies” as a blanket term for proposed government action.

Whether governments should undertake such efforts—and how these efforts should be paid for—are matters on which the American public can and does express preferences. Policymakers may choose to take public sentiment into account if they have access to reliable measurements of the public’s preferences, and this report describes new evidence gathered for exactly this purpose.

Americans have been living with the consequences of natural disasters for generations, and, as shown below, three in four Americans say they have personally observed effects of climate change. It is fully plausible that they may have policy preferences shaped by historical responses and their own experiences. But climate change puts a new spin on these disasters, because its existence, unchecked, foretells increases in both the frequency and severity of damaging events. This added dynamic raises the interesting possibility that Americans might be more supportive of government efforts to prevent damage from wildfires and floods and to assist people after a disaster if the question is framed in terms of the likely impact of climate change. We tested that possibility in the survey described in this report.