Judith Curry: IPCC Will Be ‘Toast’ If It Doesn’t Warm Soon
“The IPCC has thrown down the gauntlet – if the pause continues beyond 15 years , they are toast.”
The Earth has changed in “unprecedented ways” since 1950, the U.N. says, and its scientists are 95 percent certain that humans are responsible.
Yet the planet has largely stopped warming over the past 15 years, data shows – and a landmark report released Friday by the U.N.’s climate group could not explain why the Mercury has stopped rising.
Global surface temperatures rose rapidly during the 70s, but have been relatively flat over the past decade and a half, rising only 0.05 degrees Celsius (0.09 degrees Fahrenheit) per decade according to data from the U.K.’s weather-watching Met Office, a trend current models of the world’s climate have been unable to predict. A draft of the report leaked in early September acknowledged that trend and put it bluntly: We simply can’t explain it.
“Models do not generally reproduce the observed reduction in surface warming trend over the last 10–15 years.”
But a final draft of the report released Friday morning by the U.N.’s Intergovernmental Panel on Climate Change (IPCC) strips out the failure of models and explains away the downward trend.
“Due to natural variability, trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends,” the new report reads.
A section that suggests volcanoes and solar activity may have affected the warming has also been removed in the final version.
Climate skeptics have seized upon the change in world weather patterns, some citing it as evidence that global warming itself has decelerated or even stopped. Benny Peiser, director of the Global Warming Policy Foundation, said the slowdown was a far larger issue than the report shows.
“Unless global temperature will begin to rise again in the next few years, the IPCC is very likely going to suffer an existential blow to its credibility,” he said. Judith Curry, professor and chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, was even blunter.
“IPCC has thrown down the gauntlet – if the pause continues beyond 15 years (well it already has), they are toast.”
Many governments had objections over how the issue was treated in earlier drafts and some had called for it to be deleted altogether. In a Friday morning presentation of its findings, Thomas Stocker, co-chair of the group that wrote the report, defended that decision, the Associated Press reported.
“An old rule says that climate-relevant trends should not be calculated for periods less than around 30 years,” Stocker said.