The day after Thanksgiving, the White House made public the Fourth National Climate Assessment, Volume II. Congress has mandated that these reports be released every four years, and the Trump administration seemingly figured that doing so on the day after Thanksgiving would limit public attention. But, as the report makes clear, the growing toll of human-caused climate disruption is something we can’t ignore, and our actions over the next few years will determine how much we suffer.
The National Climate Assessment comes from the US Global Change Research Program, which consists of 13 federal agencies and receives extensive input from external experts and stakeholders. The inclusion of agencies addressing agriculture, transportation, health, and international affairs – as well as energy and the environment – in the GCRP recognizes that climate change affects all areas of our lives. Indeed, that’s one of the key messages of the assessment: That impacts in multiple sectors compounds the harm caused by warmer temperatures, sea level rise, and the droughts, wildfires, and hurricanes that are now far more damaging.
Another key message is that climate disruption harms the economy, and we could lose up to one-tenth of GDP by 2100. Estimated costs include $141 billion from heat-related deaths, $118 billion from sea-level rise, and $32 billion from infrastructure damage. Some of the costs will come from headline-making disasters, but others will come from illnesses linked to worsening air quality and increased transmission of diseases. The assessment’s Health summary notes that these effects will be widespread, and will disproportionately impact populations that already face challenges:
Changes in temperature and precipitation are increasing air quality and health risks from wildfire and ground-level ozone pollution. Rising air and water temperatures and more intense extreme events are expected to increase exposure to waterborne and foodborne diseases, affecting food and water safety. With continued warming, cold-related deaths are projected to decrease and heat-related deaths are projected to increase; in most regions, increases in heat-related deaths are expected to outpace reductions in cold-related deaths. The frequency and severity of allergic illnesses, including asthma and hay fever, are expected to increase as a result of a changing climate. Climate change is also projected to alter the geographic range and distribution of disease-carrying insects and pests, exposing more people to ticks that carry Lyme disease and mosquitoes that transmit viruses such as Zika, West Nile, and dengue, with varying impacts across regions. Communities in the Southeast, for example, are particularly vulnerable to the combined health impacts from vector-borne disease, heat, and flooding. Extreme weather and climate-related events can have lasting mental health consequences in affected communities, particularly if they result in degradation of livelihoods or community relocation. Populations including older adults, children, low-income communities, and some communities of color are often disproportionately affected by, and less resilient to, the health impacts of climate change.
The assessment is also clear about the fact that actions we take now – including regulating greenhouse-gas emissions and investing in clean energy – will determine how much devastation we experience in the future. “Adaptation and mitigation policies and programs that help individuals, communities, and states prepare for the risks of a changing climate reduce the number of injuries, illnesses, and deaths from climate-related health outcomes,” the authors write.
We need political leadership that will use this information to advance policies that mitigate damage from climate disruption. Instead, members of the Trump administration have tried to minimize and discredit the assessment. President Trump himself stated, “I don’t believe it.” As one of the report’s authors, Texas Tech University atmospheric scientist Katharine Hayhoe, pointed out, climate change is real whether we believe in it or not – and “If our decisions are not based in reality, we are the ones who will suffer the consequences.”