The United Nations-sponsored International Panel on Climate Change (IPCC), the world’s authority on the greenhouse effect, released a summary of the first volume of a comprehensive report on climate change on Friday. Its findings: Scientists can say with “extreme” confidence that humans are the dominant cause of global warming.
In its 2007 assessment, the IPCC said that global warming was “very likely” manmade. According to scientists, improved research capabilities during the time between their last report and this have increased the evidence for the anthropogenic contribution to global warming.
This year, the IPCC reports that “It is ‘extremely likely’ that human influence has been the dominant cause of the observed warming since the mid-20th century.” In other words, the IPCC has 95 percent certainty.
Scientists have comprehensive records for the period from 1950 to the present. Used in conjunction with paleoclimate reconstructions extending back hundreds to millions of years, scientists can get a comprehensive understanding of changes in the atmosphere, ocean, cryosphere (frozen portions), and on land.
According to the report, “Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes… This evidence for human influence has grown since AR4 [IPCC’s fourth assessment report].”
Scientists find it “extremely likely” than more than half of the increase in the global average surface temperature from 1951 to 2010 is the result of the anthropogenic increase in greenhouse gases and other human contributions.
The report projects a global average temperature rise of 0.3 to 4.8 degrees Celsius by the end of the century, and a sea level rise of 10 to 32 inches.
Predictably, climate change deniers have been out in force this week, pending the release of the IPCC report, with some deniers not even arguing about the human influence on global warming, but about the existence of climate change at all.
As Slate reports, James Delingpole, of The Telegraph, wrote an article this week attacking the IPCC’s “computer models,” which, he says, have long been the source for the IPCC’s “scaremongering.” Slate’s Phil Plait, an astronomer and author, deconstructs Delingpole’s claims in his own article from this week.
Delingpole is an English major and an avid proponent of the notions that climate change has not existed since 1998, and that environmentalists are killing the planet. Paradoxically, his biographical summary states that “James Delingpole is a writer, journalist and broadcaster who is right about everything.”
Delingpole once said that “It is not my job to sit down and read peer-reviewed papers because I simply haven’t got the time… I am an interpreter of interpretations.”
Of course, Delingpole represents only a minute fraction of the climate denial machine. Skeptical Science released a report last week on the 5 stages of climate denial, in anticipation of the inevitable outcry from deniers this week, which lists several climate denial stories released recently.
Also earlier this week, a new study led by Jason West, of the University of North Carolina at Chapel Hill, revealed that cutting carbon emissions would save millions of lives. Researchers found that correlations between mortality and air pollution present yet another advantage to curbing greenhouse gases: protecting human health.
West said he hopes his study might “strengthen the arguments for action” on climate change, as, apparently, the potential destruction of the environment that gives us life is not a strong enough argument for some deniers.
Alisha is a writer and researcher with Ring of Fire. Follow her on Twitter @childoftheearth.
