Humans must be to blame for climate change, say scientists

Steve Connor in the Independent (UK): Climate scientists have delivered a powerful riposte to their sceptical critics with a study that strengthens the case for saying global warming is largely the result of man-made emissions of greenhouse gases.

The researchers found that no other possible natural phenomenon, such as volcanic eruptions or variations in the activity of the Sun, could explain the significant warming of the planet over the past half century as recorded on every continent including Antarctica.

…The study updates a 2007 report by the Intergovernmental Panel on Climate Change and has discovered several new elements of the global climate which have been influenced by humans, such as an increasing amount of water vapour evaporating from the warmer oceans into the atmosphere and a corresponding increase in the saltiness of the sea.

…Scientific observations based on temperature recordings on every continent, as well as thermometer readings on, in and above the oceans, leave "little room for doubt" that the earth is warming, but trying to attribute a cause for this global warming is not possible unless man-made activity in the form of carbon dioxide emissions is taken into account, the scientists said.

The review, led by Peter Stott of the Met Office Hadley Centre in Exeter, found the "fingerprints" of human activity on many different aspects of climate change, including the overall warming of the Antarctic recently documented for the first time by other researchers.

....Asked whether climate sceptics would agree with the findings, Dr Stott said: "I just hope people look at the evidence of how the climate is changing in such a systematic way. I hope they make up their minds on the scientific evidence."

The Mertz Glacier in Antarctica, back in 2007, well before the recent calving event. Shot by Jacques.verron, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license