It is no surprise that the world is warming. Surface temperatures have been inching steadily upwards at least since the 1970s, with the 10 warmest years on record occurring since 2005. Higher thermometer readings are one sign of warming, but they tell only a little of the story.
As Earth’s atmosphere warms, 90% of the added heat energy disappears into the oceans, hiding the warming temporarily, but affecting the planet all the same. The oceans are warming, too, rising inexorably and at a faster pace today than in the 20th century. Cruise ships now cross Arctic oceans once thought impassable. Glaciers are shrinking at an alarming rate around the world. Extreme heat waves with never-before-seen temperatures as high as 120 degrees now kill marine life along the northwestern Pacific Coast and devastate entire towns inland. Here in California, formerly carefree summers now bring megafires and choking smoke. Even rainfall has become more extreme, like last weekend’s 17-inch downpour that killed over 20 in Tennessee.
Humans are “unequivocally” responsible for most of the warming, according to a major report released this month from the Intergovernmental Panel on Climate Change (IPCC,) a unit of the United Nations. The report’s alarming conclusion is that we have put so much greenhouse gas into the atmosphere that the planet must continue to warm into the 2030s. The situation is not without hope, however. The report also tells us that we can take action now to slow warming after the 2030s, with the possibility of protecting our children and their children from some of the climate extremes that the world will face otherwise.
The report is called the IPCC Sixth Assessment Report. It should be a matter of local pride that key input to this and all previous IPCC reports came from climate scientists at Lawrence Livermore National Laboratory (LLNL). In 1995, LLNL’s Ben Santer helped establish the “balance of evidence” that there is “discernible human influence” on warming. The evidence has grown far stronger with the passing years, leading to the Sixth Assessment assertion that it is unequivocal.
LLNL oceanographer Paul Durack is lead author of the Sixth Assessment Report’s chapter covering human influence on climate. Other contributors from LLNL include Celine Bonfils, Peter Gleckler, Mark Zelinka and Santer.
Local pride aside, it is a matter of the highest importance that we accept and act on the information contained in the Assessment Report. The quality of life of the Earth’s future inhabitants depends on it.