On Thursday, scientists discovered that a huge mass of ice four times the size of Manhattan had broken free of Petermann glacier in northwestern Greenland. The “ice island” was the largest calving event on the glacier since 1962, and researchers estimated Petermann lost nearly a quarter of its floating ice tongue in one go.
Any individual calving event, like a bad storm, wildfire, or flood, is not necessarily a symptom of global warming. But large bergs also crumbled off Petermann in in 2001 and 2008, and Jason Box of Ohio State University has been studying the glacier — and expecting this breakup event — for some time. He said the glacier’s behavior in recent years is “all part of a climate warming pattern.”
As it turns out, the new ice island was born just in time for the 35th anniversary of the scientific paper that coined the term “global warming.” On August 8,1975, the journal Science published the article entitled “Are We on the Brink of a Pronounced Global Warming?” by Wallace Smith Broecker of Columbia University.
Concerns about man-made global warming had been uttered before, from the halls of Congress to educational science videos, but Broecker’s work laid out the issue in stark terms and it came with a prediction for the future. Here is his remarkably simple, elegant abstract:
The first caveat about man-made dust is still something climate scientists debate. Its ability to block sunlight dampens the effects of greenhouse gases somewhat, but CO2 swamps this effect, and the temperature records are fairly undeniable (see below).
Though Broecker eschews much of the media attention that comes with being heralded as one of the “fathers of global warming,” his contribution is hard to overstate. In a stroke he offered a glimpse of what climate science was (and is, now more than ever) capable of: not only understanding past changes in the Earth system, but predicting how that system will behave in the future.
Broecker’s predictions proved to be pretty accurate. A figure from his paper suggests that global temperature anomalies might be about 0.8 degrees Celsius (1.4 degrees Fahrenheit) by 2010:
By comparison, the latest data from NASA’s Goddard Institute of Space Studies shows that temperatures have climbed about 0.6 C since the 1940s and 0.8 C since the 1880s (the zero in the figure below is a measure of average monthly temperature from 1951-1980. Explanation here.):
At the time, the science of climate prediction was far less refined than it is today. And yet for the most part, Broecker got it right:
It is perhaps fair that the businesses, governments, and people of the world did not instantly heed his warning. After all, it was just one single scientist writing one single article, right?
Thirty-five years later, Broecker’s predictions have turned out more or less as he
called them (and thousands of scientific papers now back up the trend he
identified). The phrase “global warming” itself has become so
politically charged that all the temperature records, tide gauges, and
satellite photos of crumbling and melting Petermann glaciers in the world can’t convince anyone
who isn’t already that climate change is proceeding in earnest, and
that it must be urgently dealt with. Instead of “redoubled efforts,” failed climate talks, legislation, and economic hand-wringing are the norm.
Broecker has moved on. He is researching ways that we can capture and store carbon dioxide from the atmosphere — new ideas and technologies that will forestall catastrophic climate change and allow our civilization to continue to live and prosper on this planet.
Maybe it’s time we finally took a page out of his book.
; Science; NASA