Global warming could delay next ice age, say scientists

BBC : According to research published in Nature Geoscience, human carbon emissions could insulate Earth against the next ice age, writes Richard Black for the BBC. Ice ages result because of subtle variations in Earth’s orbit, although exactly how those variations cause global temperature change is not known. The next ice age should begin within about 1500 years, say Luke Skinner of Cambridge University and colleagues, but it will likely be deferred because of the abnormally high level of atmospheric carbon dioxide, currently around 390 parts per million; that would have to drop to below about 240 ppm before glaciation could begin. And other research groups have shown that even if emissions were cut instantly, CO ₂ concentrations would remain elevated for at least 1000 years. Despite the fact that delaying an ice age may sound desirable, says Skinner, humans are doing too good a job of heating the planet: “We’re . . . not maintaining our currently warm climate but heating it much further, and adding CO ₂ to a warm climate is very different from adding it to a cold climate. The rate of change with CO ₂ is basically unprecedented, and there are huge consequences if we can’t cope with that.”