November 22, 2017

It’s he-e-e-re: National Assessment says climate change has arrived, and we’re responsible

A recently issued National Climate Assessment, authored by a team of more than 300 experts guided by a 60-member Federal Advisory Committee, concludes that climate change is already here, and human activities are largely responsible:

“What is new over the last decade is that we know with increasing certainty that climate change is happening now. While scientists continue to refine projections of the future, observations unequivocally show that climate is changing and that the warming of the past 50 years is primarily due to human-induced emissions of heat-trapping gases. These emissions come mainly from burning coal, oil, and gas, with additional contributions from forest clearing and some agricultural practices.”

In our own area, the most striking impact of climate change so far has been an increase of heavy precipitation events: 71% between 1958 and 2010. The report projects that there will be future increases in flooding and stresses placed on fisheries and agriculture–two important local economic mainstays–as well as infrastructure.

The report concludes that temperatures will rise another 2°F to 4°F in most areas of the United States over the next few decades, but points out that some of this warming could be reduced specifically by reductions in emissions of soot and methane (the principal component of natural gas), which have a much shorter atmospheric lifetime than carbon dioxide. But even under a lower emissions scenario, the report concludes that there will be another 3°F to 5°F  rise by the end of the century, with as much as a 10°F rise in the worst-case scenario.

While noting that adaptive strategies will be necessary in any case, given that a good deal of climate change is already baked into the cake, the report stresses that the cost and difficulty of adaptation can be greatly reduced by mitigating the degree of future global temperature increases–which of course means reducing greenhouse gas emissions.

Read the full report here

The report has been covered by a variety of media including:

Time http://time.com/89823/national-climate-assessment-extreme-weather/
Washington Post http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2014/05/06/national-climate-assessment-15-arresting-images-of-climate-change-now-and-in-the-pipeline/
New York Times http://www.nytimes.com/2014/05/07/science/earth/climate-change-report.html?_r=0