Hi Flann, that is easy. Natural climate change is driven by earth’s orbital cycles. When northern summer is at perihelion, closest to the sun, the snow that fell in winter melts and glaciers retreat. When northern summer is at aphelion, furthest from the sun, the snow that fell in winter does not melt, and glaciers advance. This is called the Milankovitch Cycle. Now, when the orbital warming or cooling factor gets going, it produces other impacts, such as albedo, or whiteness. When there is lots of snow the earth reflects more sunlight and gets colder, and vice versa. Also, it affects the ocean carbon cycle.Flann 5 wrote:One of the main arguments against man made global warming is that historically co2 increases in the atmosphere have followed not preceded periods of warming. I would be interested to hear a response to this argument from those who hold to man made global warming.
http://www.yaleclimateconnections.org/2 ... te-system/ is a very good simple science article you can read to get more detail. It states that “Initial temperature changes at the beginnings and ends of ice ages are caused by changes in orbital forcings. These temperature changes have effects on the natural carbon, nitrogen, and methane cycles. In particular, initial warming reduces ocean uptake of atmospheric carbon (because warmer water can absorb less CO2 from the atmosphere), and warmer temperatures increase the decay rate of vegetative matter. Similarly, cooling at the start of an ice age increases ocean uptake and reduces emissions from vegetative decay.”
That is why in natural climate change the CO2 increase comes after orbital warming. Our current addition of ten gigatonnes of carbon every year is producing the same warming feedback loop over decades which over previous geological time scales took thousands of years.
