The Third U.S. National Climate Assessment

The Washington Post reported yesterday that the Third U.S. National Climate Assessment (NCA3)  published a rather dire scientific report Friday detailing the growing threats of climate change. The report stands in stark contrast to the administration’s efforts to downplay humans’ role in global warming, withdraw from an international climate accord and reverse Obama-era policies aimed at curbing U.S. greenhouse-gas output.

The Fourth U.S. National Climate Assessment (NCA4) will provide more regionally-specific analysis on the effect of Climate Change for the United States, whereas the NCA3 report, all 477 pages of it, is recommended for those “who have a technical background in climate science.” I read the, so you don’t have to, and here are some of the highlights:

  • It is "extremely likely" that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century
     
 
Climate Change Causes.png
  • The 2015 Paris climate conference would have enabled us to limit global warming to 3.6°F (2°C) above preindustrial levels. The Paris Climate Conference would have been unable to do this on its own; our success would have depended on follow-up agreements after 2030, but without the Paris agreement, there is virtually no chance.
  • The global average sea level has risen by about 7–8 inches since 1900, with almost half (about 3 inches) of that rise occurring since 1993. Global average sea levels are expected to continue to rise—by at least several inches in the next 15 years and by 1–4 feet by 2100. Sea level rise will be higher than the global average on the East and Gulf Coasts of the United States. 
  • Annual trends toward earlier spring melt and reduced snowpack are already affecting water resources in the western United States and these trends are expected to continue. Under higher scenarios, and assuming no change to current water resources management, chronic, long-duration hydrological drought is increasingly possible before the end of this century.
  • Between 1901 and 2016, the global average temperature has increased by 1.8°. Without major reductions in emissions, the increase in annual average global temperature relative to preindustrial times could reach 9°F (5°C) or more by the end of this century.  If no changes are made, but greenhouse emissions are stabilized, then temperatures will still raise by 1.1°F (0.6°C).
     
 
Average Temperatures.png
  • Dispelling the notion of cyclical climate evolution, record-setting warm weather has increased exponentially while record-setting cool weather has decreased.  Cold waves are predicted to become less intense while heat waves will become more intense, and the number of days below freezing is projected to decline while the number above 90°F will rise.
 
Record Temperatures.png
  • Analysis of proxy-based records (e.g. from tree rings, fossil pollen, corals, ocean and lake sediments, and ice cores), of historic temperatures also dispels the notion of cyclical climate change.  The image below show the trend of temperatures throughout history.
 
Temperature Trends.png
  • While net-snowfall has remained roughly the same, it has been moving further and further north, become more extreme (i.e. more snowfall in a shorter time frame), and has a season that ends significantly earlier.  Rainfall follows a similar pattern, with more extreme precipitation (defined as large amounts of rainfall taking place over 5 days) throughout a shorter rainy season. The resulting sporadic, and extreme, precipitation will likely lead to more nuisance flooding, droughts, and wildfires. Nuisance and tidal flooding have increased 5- to 10-fold since the 1960s in several U.S. coastal cities and are expected to increase in depth, frequency, and extent this century.
Extreme Rainfall.png

Meanwhile, the U.S. continues to attempt to deny the existence of climate change while Chinese leadership assumes the mantle of combating it, and Russia repositions its naval and air forces, and petroleum industry, to benefit from it.  The current Secretary of Defense, Mattis, at least recognizes the instability that Climate Change can bring, but he seems decidedly alone in this Administration. Instead the administration seems content on rebuilding methods of energy production that have been on their way out (like Coal) and insisting on allowing the free market and consumer consumption reductions to combat the issue.

Unfortunately, consumer consumption reductions alone cannot stop or reverse Climate Change.  This is a global crisis that requires a global response - starting with our elected officials. Vote for Democrats or Common-Sense Republicans at your local, state, and federal levels.  If you have the ability:  Donate to their campaigns.