Top Ten Take-Aways from the Pending National Climate Assessment

This morning The New York Times published a draft copy of the latest National Climate Assessment, a report Congressionally-mandated once every four years that updates the country on the latest scientific research and understanding on climate change. Not surprisingly, the findings in the latest report are alarming. Also not surprising, as reported by the Times, is the pervasive suspicion and fear throughout America’s government and scientific community that the Trump administration may seek to ignore, bury or even refute the fact-based findings in the report.
So without further ado, before Trump or his fossil fuel industry cronies can bury the truth, here are ten key take-aways from the final draft of the pending National Climate Assessment:
- “Humanity is conducting an unprecedented experiment with the Earth system through the large-scale combustion of fossil fuels and widespread deforestation and the resulting release of carbon dioxide (CO2) into the atmosphere.”
- “[I]t is extremely likely that human influence has been the dominant cause” of warming since the middle of the last century and “there are no convincing alternative explanations” for that warming.
- “Average annual temperature over the contiguous United States has increased by 1.2°F (0.7°C) for the period 1986–2016 relative to 1901–1960 and by 1.8°F (1.0°C) based on a linear regression for the period 1895–2016.”
- “Extreme temperatures in the contiguous United States are projected to increase even more than average temperatures. The temperatures of extremely cold days and extremely warm days are both expected to increase. Cold waves are projected to become less intense while heat waves will become more intense. The number of days below freezing is projected to decline while the number above 90°F will rise.”
- “Global mean sea level (GMSL) has risen by about 7–8 inches (about 16–21 cm) since 1900, with about 3 of those inches (about 7 cm) occurring since 1993.”
- “Relative to the year 2000, GMSL is very likely to rise by 0.3–0.6 feet (9–18 cm) by 2030, 0.5–1.2 feet (15–38 cm) by 2050, and 1 to 4 feet (30–130 cm) by 2100.
- Emerging science regarding Antarctic ice sheet stability suggests that, for high emission scenarios, a GMSL rise exceeding 8 feet (2.4 m) by 2100 is physically possible, although the probability of such an extreme outcome cannot currently be assessed.”
- “As sea levels have risen, the number of tidal floods each year that cause minor impacts (also called “nuisance floods”) have increased 5- to 10-fold since the 1960s in several U.S. coastal cities (very high confidence). Rates of increase are accelerating in over 25 Atlantic and Gulf Coast cities (very high confidence). Tidal flooding will continue increasing in depth, frequency, and extent this century.”
- “Significant advances have also been made in our understanding of extreme weather events and how they relate to increasing global temperatures and associated climate changes. Since 1980, the cost of extreme events for the United States has exceeded $1.1 trillion . . . .”
- “[A]gricultural production is increasingly disrupted by climate and extreme weather events, and these effects are expected to be augmented by mid-century and beyond for most crops. Precipitation extremes put pressure on agricultural soil and water assets and lead to increased irrigation, shrinking aquifers, and ground subsidence.”
These findings give us only one option: We must move America off fossil fuels, now. Our planet depends on it.