The European Environment Agency says the average temperature on the continent in the last decade was already 1.3 degrees Celsius above the preindustrial level. The vast majority of glaciers in Europe are retreating; river flows are decreasing throughout Southern and Eastern Europe.

"By the late 21st century, European plant species are projected to shift several hundred kilometers to the north, forests are likely to contract in the south and expand in the north, and about half of the mountain plant species may face extinction," the EEA says.

Farmers in the U.S. Midwest have just endured the worst drought in 50 years; the bread baskets of Ukraine and Russia have similarly shriveled in the face of intense heat.

Technologies exist that will allow humanity to make a rapid dent on emissions. Renewable energy accounts for double the amount of power it did just six years ago. Carbon sinks deep underground can capture and store emissions from gas flaring. Better vehicle emissions standards, reforestation and a developed carbon trading market would all help.

There are all sorts of green gestures at the 18th meeting of the United Nations Framework on Climate Change in Qatar, one of the world's highest emitters of carbon dioxide per capita. Examples are "paperless" documentation and buses run on natural gas to ferry delegates to the conference center, which is partly powered by solar panels. But the political will required of 194 delegations to bring the world closer to a new climate pact is yet to be tested.