Hurricane Katrina revealed what is to come for this country from global warming. As super-hurricanes become common and sea levels rise in a warmed world, all our great Gulf and Atlantic Coast cities are at risk for the same fate as New Orleans. On our current greenhouse gas emissions path, we face 100 Katrinas.
That’s one reason Climate Progress is being launched today. On a personal level, Katrina’s ferocious storm surge destroyed the Mississippi home of my brother, his wife, and son as they huddled in a Biloxi shelter. Katrina’s brutal aftermath spurred me to dig more widely and more deeply into the subject.
While I have spent most of the last two decades working on climate solutions, my Ph.D. thesis was on physical oceanography, researched at the Scripps Institution of Oceanography. I talked to the world’s leading climate scientists and reviewed the growing body of scientific evidence, which in turn led to a book, Hell and High Water: Global Warming–The Solution and the Politics (William Morrow, January 2007) and to this blog.
What did I learn?
A very short version can be found in an op-ed the Miami Herald published at the start of the 2006 hurricane season. It seems particularly relevant with a storm bearing down on Florida. Here are the key points:
Since the 1970s, the number of intense Category 4 and 5 Atlantic hurricanes has nearly doubled. Hurricanes are heat engines that draw their power from the warm, moist water beneath them. The warmer the water, the more intense the hurricane. Statistical analysis reveals the major cause of the increase in hurricane intensity is rising sea surface temperatures.
Since the 1970s, the Atlantic’s hurricane-forming region has warmed nearly 1 degree Fahrenheit. Recent research attributes nearly all that warming to increasing emissions of heat-trapping greenhouse gases from human activity.
As the sea surface temperature increases, we are also seeing longer hurricane seasons. In 2005, Emily became the only known Category 5 Atlantic hurricane to form in July. Zeta was the longest-lived January tropical cyclone on record.
A fraction of the recent warming may be due to natural cycles, but on our current emissions trend, the Atlantic will warm another 2 degrees Fahrenheit by mid-century, and more than double that by 2100. If we don’t act fast, global warming will utterly overwhelm the natural cycles. The moderate hurricane seasons of the 1960s and 1970s are a thing of the past. Four or more Atlantic super-hurricanes — Category 4 or stronger — a year is likely to be the norm by 2025.
The devastation of Katrina showed what havoc a super-hurricane can wreak when it hits a city that’s largely below sea level. Just a few years ago, scientists projected a mean sea level rise of 20 inches, with little or no contribution from the huge ice sheets of Greenland and Antarctica.
Today we know the ice sheets are melting much faster than predicted. Both Greenland and Antarctica are already contributing to rising seas. Greenland’s disintegration could become irreversible by mid-century, which would eventually raise sea levels 20 feet. That would inundate one quarter of Florida….
Climate Progress will elaborate on these and other aspects of climate science, as well as on the climate solutions needed to avoid this catastrophe and the climate politics that will ultimately determine whether we act in time.