Climate feedback loops could add 30% to global warming

A study reported by The Guardian warns that natural climate feedback loops could increase global warming by 30 percent. A second, reported by ScienceDaily, finds that a climatic link between the Indian and Pacific oceans that held for 400 years is breaking down under human-caused warming. A third, reported by ScienceBlog.com, comes from French nectarine orchards, where solar panels were tilted flat over the trees on nights when frost was forecast.

The three are separate pieces of work, not variations on one experiment, and none of them settles the others. What they share is a view of the climate as a system that reacts: to heat, with more heat; to warming, by rearranging how heat and moisture move across the planet; and, in the orchard case, to a well-timed mechanical intervention.

The warming that arrives on its own schedule

The Guardian study concerns feedback loops, meaning warming that triggers further emissions from the earth itself. The sources named are methane and carbon dioxide released from natural reservoirs such as thawing permafrost and warming oceans.

The warning attached to the finding is about timing as much as size. If those releases add to the total, the planet could reach critical temperature thresholds faster than current human-led emission models predict. That phrase is the argument in miniature: human-led emission models track what people put into the atmosphere, while the study points at a second contribution that comes from the warmed planet rather than from industry or transport.

As reported, the 30 percent figure is an estimate of additional warming rather than a measurement of it, and the summary does not name the thresholds it refers to. The claim is about pace, not a new temperature target. More on the feedback-loop study.