03 December 2018

Climate Change Report Vol. 1

The second volume of the Fourth National Climate Assessment was released on 23 Nov 2018, the day after Thanksgiving. A version of this post appeared on www.warrensnotice.com shortly after the first volume was released in 2017. It stands on its own and set the stage.

Welcome back. Surprise, surprise. The White House approved release of the Climate Science Special Report, the first of two volumes of the Fourth National Climate Assessment. Also, apparently none of the 13 Federal agencies responsible for producing the report tried to undercut or change the findings of its scientists.

So why was this all a surprise? In sharp contrast to the president’s words and his administration’s policies, the report’s executive summary states:

This assessment concludes, based on extensive evidence, that 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. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence. [Bold type is from the report.]
Surface temperature change (in °F) for 1986–2015 relative to 1901–1960 from the NOAA National Centers for Environmental Information. (Graphic from Climate Science Special Report.)
Origin of Climate Report
It’s easy to forget that, once upon a time, Republican presidents were the environmental good guys. In 1970, for example, Richard Nixon created the Environmental Protection Agency, and he did it by executive order. The consensus is that his motivation was truly environmental.

Even closer to the topic, Ronald Reagan and George H.W. Bush actively promoted measures to combat climate change. One major action was the U.S. Global Change Research Program (USGCRP), established by presidential initiative in 1989 and mandated by Congress in the Global Change Research Act of 1990.

Member agencies of U.S. Global
Change Research Program.
The USGRP directed 13 Federal agencies to develop and coordinate a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change.

One mandated product of the USGRP is the National Climate Assessment. Every four years, the agencies prepare a report that analyzes both the effects of global change and the human-induced and natural trends in global change for the subsequent 25 to 100 years.

Fourth National Climate Assessment
The Climate Science Special Report is an authoritative, comprehensive 470-page, 15-chapter, 5-appendices assessment of the science of climate change with a focus on the United States. It was prepared by scientists in government and academia and peer-reviewed by the National Academy of Sciences.

Selected Key Findings
Each chapter of the report includes key findings with confidence statements. I’ve taken excerpts from several findings of high or very high confidence to convey the significance of the issues.

- [A]verage temperatures in recent decades over much of the world have been much higher, and have risen faster…than at any time in the past 1,700 years or more
- It is extremely likely that more than half of the global mean temperature increase since 1951 was caused by human influence on climate
- Stabilizing global mean temperature to less than 3.6°F (2°C) above preindustrial levels requires substantial reductions in net global CO2 emissions prior to 2040 relative to present-day values and likely requires net emissions to become zero or possibly negative later in the century
- The frequency and intensity of heavy precipitation events are projected to continue to increase over the 21st century
- Plant productivity has not increased commensurate with the increased number of frost-free days or with the longer growing season
- Arctic-wide ice loss is expected to continue through the 21st century, very likely resulting in nearly sea ice-free late summers by the 2040s
- Global mean sea level (GMSL) has risen by about 7 to 8 inches since 1900, with about 3 of those inches occurring since 1993
- Relative to the year 2000, GMSL is very likely to rise by 0.3–0.6 feet by 2030, 0.5–1.2 feet by 2050, and 1.0–4.3 feet by 2100 (very high confidence in lower bounds)
- Tidal flooding will continue increasing in depth, frequency, and extent this century.

Muir Glacier, Alaska, photographed by
U.S. Geological Survey in 1941 and 2004.

Climate Science Special Report.)
Wrap Up
The concern is that we’ve passed the global climate tipping point. Whereas the Paris climate agreement aimed to limit global warming to 3.6°F (2°C) above preindustrial levels, the UN climate negotiators are now forced to consider 5.4°F (3°C). The sea-level rise alone would impact hundreds of millions of people.

Although certain US states, cities and businesses are trying to step in to fill the role abdicated by our federal government, coordinated global action is critical. Let’s hope the report’s release signals a change. Thanks for stopping by.

Fourth National Climate Assessment, Volume I--Climate Science Special Report: science2017.globalchange.gov/
The U.S. Global Change Research Program for Fiscal Year 2017: downloads.globalchange.gov/ocp/ocp2017/Our-Changing-Planet_FY-2017_full.pdf
Richard Nixon and the EPA: www.ontheissues.org/celeb/Richard_Nixon_Environment.htm
Reagan and Bush (41) on climate change policy: nsarchive2.gwu.edu/NSAEBB/NSAEBB536-Reagan-Bush-Recognized-Need-for-US-Leadership-on-Climate-Change-in-1980s/
Article on the 3°C world on The Guardian website: www.theguardian.com/cities/ng-interactive/2017/nov/03/three-degree-world-cities-drowned-global-warming?CMP=share_btn_tw
Interview with Al Gore re: Trump and climate on The Guardian website: www.theguardian.com/environment/2017/nov/10/al-gore-donald-trump-climate-change

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