Climate, Ready for Departure

I always chuckle when physicists start talking subatomic measurements and the conversation turns to oogles and oogleplexes, barns and sheds.  Scientists frequently have vivid ways to describe their findings, and it can be fun listening.  The latest addition to that language, though it’s not nearly so much fun, comes from scientists at the University of Hawaii, who have coined the term “Estimated Year of Climate Departure” (EYCD) to describe the findings of an extensive study of temperature trends globally.   It sounds rather like a fond farewell at the airport, doesn’t it. The study identifies the year when, for many major cities in the world, the lowest annual average temperature is expected to exceed the highest average annual temperature for that place in the years between1860 and 2006.  In other words, when the weather is no longer ever what it used to be and it starts getting really hot!

The Hawaii scientists reported on their findings last week in Nature, and their results are  summarized in the chart above.  Their study assumes a constant steady trend in temperature according to historical averages prior to 2006.   The results have been reviewed and validated by other scientists and found precise within plus or minus five years, but it should be noted that recent acceleration in temperature changes may make departure sooner rather than later.  Even assuming only the long-term historical trend, the results surprised the scientists themselves.  The EYCD “tipping point” came much earlier than expected, particularly in the tropics.  The tropics are significant, because tropical species from monkeys to banana trees are used to constant year round temperatures and much more sensitive to temperature variation than moderate climate species.  First in line for boarding are Kingston, Jamaica (not shown on the chart) and cities in Indonesia.  But my neighborhood, Washington DC, boards in 2047 and  San Francisco in 2049, and Anchorage Alaska only gets to enjoy polar bears until 2071.

A separate chart depicts EYCD if vigorous climate change mitigation is pursued.  It turns out that climate change mitigation efforts delay EYCD in most places by about 30 years, but eventually it happens everywhere.  We’re in for a hot next several hundred years (unless Tipping Point Theory kicks in and the melting of all the glaciers, halting ocean currents, produces both extreme heats and extreme colds with mega-storms in between.)  Meanwhile, sea levels are rising at a rate the UN science panel now says will produce a 10 foot rise by 2100.  It should be noted that most locations in New York City currently vary between three and eight feet above sea level.

The policy question is what to do about it.  Should we invest heavily in defensive infrastructure or withdraw from coasts, air condition everything and wait several hundred years for climate rebalancing to occur.  Either way of course we have to stop pouring more carbon dioxide into the atmosphere.  These are the things we should be discussing now in DC, not defunding ObamaCare.  Ken Burns, in his PBS series about the dust bowl, noted how many in Washington in the 1930s saw the situation in Kansas and Oklahoma as hopeless and wanted simply to abandon the Midwest, leaving it as a desert.  FDR wisely chose otherwise, and government-funded advances in agricultural sciences made dust bowls a thing of the past.  I’m inclined to go FDR’s route of hope and expect breakthroughs in our science, but the challenges are immense and we need to get working on them right away.  The “Ready for Departure” is already sounding.