The Earth has natural cycles of glaciation that we can pin down by looking at Earth’s orbital patterns around the sun. The ice goes in, the ice goes out, as the Earth heats and cools naturally. When it comes in, we have an ice age. We’ve been in a warm period for about 11,000 years now and we should be due for an ice age in about 1,500 years. Except we’re not because we’ve trapped too much heat already in our atmosphere for things to cool properly. According to a just-out paper in Nature Geoscience, that next ice age is going to be delayed by tens of thousands of years. This is not actually good news.What it means is that things will keep melting on planet Earth. Nature won’t be providing us with a get out of global warming jail free card. “Ice sheets like those in western Antarctica are already destabilized by global warming,” says Jim Channell, of the University of Florida and one of the paper’s authors. “When they eventually slough off and become a part of the ocean’s volume, it will have a dramatic effect on sea level.”The study itself a pretty neat work of astro-geology. The researchers looked at the big drivers of past ice ages and, using Earth’s orbital patterns over the past several million years — how it tilts in and out — came up with the planet’s natural cycles of solar heating. Compare that to past glacial and interglaciel periods, and you come up with some answers. “We know from past records that Earth’s orbital characteristics during our present inter-glacial period are a dead ringer for orbital characteristics in an interglacial period 780,000 years ago,” says Channell.But, things are different now in another way: greenouse gases. We haven’t had this concentration of greenhouse gases on Earth within the last several million years. And that concentration is enough to trap enough heat such that Earth won’t be able to “turn the temperature tide” enough to start a cooling cycle.The highest concentration of greenhouse gases that’s occured on Earth naturally has been about 280 parts-per-million. We’re now at 390 parts per million, reached mostly via a dramatic spike over the past 150 years. “The problem is that now we have added to the total amount of CO2 cycling through the system by burning fossil fuels,” says Channell. "The cooling forces can’t keep up.“We haven’t seen this high concentration of greenhouse gases in the atmosphere for several million years,” he adds. “All bets are off.”Reach this writer michaelb@motherboard.tv or follow him on Twitter at @everydayelk.
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