Yet more ominous news about climate change: its most devastating effects could be in the tropics rather than in the polar regions, according to new research in Nature. This is unexpected. For more than 20 years, climate scientists have assumed that, as the world warmed, the most dramatic climbs in average temperature would be in the coldest zones, with the lowest warming around the equator. This remains the case. But plants and animals already at the limit of their temperature tolerance may suffer drastically as the mercury climbs on the thermometer.

Corals bleach in warmer-than-usual oceans, and a dead reef means a loss of habitat for thousands of species. German and US researchers studied 500 million readings from 3,000 weather stations to measure temperature increases from 1961 to 2009, and considered the effects on the metabolisms of snakes, lizards and other cold-blooded creatures. The higher the temperature, the faster their metabolic rates, and the higher the demand for food and oxygen, they report. Animals that must work harder to find food will have less energy to spend on reproduction. The implication is that climate change will step up rates of extinction. Since the tropical regions provide habitats for the greatest richness of species, the losses will be greater. This is not the only bad news. Geophysical Research Letters has now published a Met Office study of the link between heat waves and rising average temperatures. Although nations last year signed the Copenhagen accord to limit global warming to 2C – without committing themselves to real action – even this increase could trigger unprecedented extremes of heat in places such as southern Europe and North America, with the thermometer climbing 6C above the highest levels experienced today.

These are both predictions. They may turn out to be wrong, and they will not impress those who are determined to dismiss climate change as a worldwide conspiracy cooked up by the Met office, Nasa, the US National Oceanic and Atmospheric Administration, and universities and research institutes around the world. This year the legislature of South Dakota passed a resolution stating that the world had actually got cooler in the last eight years; and that "there are a variety of climatological, meteorological, astrological, thermological, cosmological, and ecological dynamics that can effect [sic] world weather phenomena".

Alas, there are governments that do accept the evidence, but have yet to act. Yes, there are uncertainties in all the climate models. But all the models, and all the data, consistently point to a warmer world, and a more dangerous one. How long can political refusal to confront the evidence continue, and at what cost?