The Federal government released its latest multi-agency report on climate change this week. The report is more bleak than past versions. Less and less of the climate change debate is focused on future projections as we start to experience the changing climate in ways that are increasingly apparent in the present. A few highlights:
Arctic Sea Ice
“Sea ice in the Arctic has decreased dramatically since the satellite record began in 1978. Minimum Arctic sea ice extent (which occurs in early to mid-September) has decreased by more than 40%. This decline is unprecedented in the historical record, and the reduction of ice volume and thickness is even greater. Ice thickness decreased by more than 50% from 1958-1976 to 2003-2008. The percentage of the March ice cover made up of thicker ice (ice that has survived a summer melt season) decreased from 75% in the mid-1980s to 45% in 2011.”
Changing frost zones
“The lengthening of the frost-free season has been somewhat greater in the western U.S. than the eastern U.S., increasing by 2 to 3 weeks in the Northwest and Southwest, 1 to 2 weeks in the Midwest, Great Plains, and Northeast, and slightly less than 1 week in the Southeast. These differences mirror the overall trend of more warming in the north and west and less warming in the Southeast.”
Carbon Emissions are the driver for warming climate
“The conclusion that human influences are the primary driver of recent climate change is based on multiple lines of independent evidence. The first line of evidence is our fundamental understanding of how certain gases trap heat, how the climate system responds to increases in these gases, and how other human and natural factors influence climate. The second line of evidence is from reconstructions of past climates using evidence such as tree rings, ice cores, and corals. These show that global surface temperatures over the last several decades are clearly unusual, with the last decade (2000-2009) warmer than any time in at least the last 1,300 years and perhaps much longer.
“The third line of evidence comes from using climate models to simulate the climate of the past century, separating the human and natural factors that influence climate. When the human factors are removed, these models show that solar and volcanic activity would have tended to slightly cool the earth, and other natural variations are too small to explain the amount of warming. Only when the human influences are included do the models reproduce the warming observed over the past 50 years.”
Yes, it still snows sometimes…
“Winter storms have increased in frequency and intensity since the 1950s, and their tracks have shifted northward over the United States., Other trends in severe storms, including the intensity and frequency of tornadoes, hail, and damaging thunderstorm winds, are uncertain and are being studied intensively. There has been a sizable upward trend in the number of storms causing large financial and other losses.”
Sea level rise
“Global sea level has risen about 8 inches since reliable record keeping began in 1880. It is projected to rise another 1 to 4 feet by 2100. The oceans are absorbing over 90% of the increased atmospheric heat associated with emissions from human activity. Like mercury in a thermometer, water expands as it warms up (this is referred to as “thermal expansion”) causing sea levels to rise. Melting of glaciers and ice sheets is also contributing to sea level rise at increasing rates.”
As the evidence of climate change becomes more immediate and undeniable and the denial more blindly obstinate, it’s worth remembering an entertaining irony. The most palatable, just, and affordable strategy for coping with the problem of climate change comes, as is so often the case, from a Libertarian economist. Ronald Coase was part of the now-legendary core of University of Chicago economists who helped bring Libertarian theory into mainstream public policy. Coase, along with his “Chicago School” colleague Milton Friedman, helped design pollution markets as an alternative to regulation.
Of course, what passed for Libertarianism a generation ago is a bit too thinky for a movement that’s been taken over by Neo-Confederates. Nevertheless, Libertarians deserve credit for cap and trade. It remains the best solution we have.