New paper: Modulation of Ice Ages via Precession and Dust-Albedo Feedbacks | Watts Up With That?: "And so now we have the entire ice age forcing and feedback mechanism, laid out and plain for all to see. It begins when a Great Summer turns into a Great Winter, which reduces the sun-strength in the northern hemisphere and allows ice sheets to grow. This is a slow process that takes tens of thousands of years, and appears destined to turn the world into a complete snowball. However, the high albedo polar ice sheets have an Achilles heel – dust. As the ice sheets grow and the seas cool, CO2 also reduces. The concentration finally reaches the critical 190 ppm level where world flora begins to die, especially at higher altitude, and the Gobi steppe-lands turn into a true sand desert. This turns northern China into the equivalent of 1930s Dust Bowl America, and the ensuing dust storms dump thousands of tonnes of dust onto the northern ice sheets each year. And so when the next Great Summer comes along, the dusty polar ice sheets can warm and melt and the next interglacial is born. So CO2 can indeed cause global warming but its effect is much more pronounced at low concentrations, rather than high concentrations."
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