In reply to Roy:
> (In reply to ALL
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> The Little Ice age 50 – 60 years in the 16th century. What caused the cooling? And why did the cooling stop and suddenly and the northern hemisphere warmed up again ?
Well, there's a growing community of scientists who believe that human activities have been impacting climate for far longer than the industrial age. Clearing land for agriculture has nearly always meant cutting down forests, or burning them, both of which releases carbon into the atmosphere. The forest is replaced by agricultural land, which locks up less carbon. In addition, tropical forests have been removed and replaced by rice paddies, which release methane, another greenhouse gas.
I've seen figures of 80%+ deforestation for Africa, for example, and similar high figures for other parts of the globe.
The Little Ice Age is still largely thought of as being mostly a Northern Hemisphere phenomenon. One theory is that the Black Death caused such an enormous loss of life that forests regrew and locked up more carbon, thereby lowering temperatures. It's also been suggested that the massive human die-off in North America caused by the arrival of Europeans (and new germs) also caused forest regrowth, and carbon fixing.
As to why temperatures warmed up again: industrialisation, growing populations, associated forest clearing and land use changes, etc. The other reasons were probably more important originally, with industrialisation growing over time.
> Why did we have an ice age 18 thousand years ago, and why did it come to a relatively quick end?
Milankovitch cycles.
> Enjoy the carbon tax hikes
And now we get to the real reason you're a denier.
The question of whether or not climate change is happening and we're the cause is an entirely scientific question, and it's the one we seem to be arguing about here. It's completely disconnected to any ideas of mitigation or adaptation. Whenever I see someone in one of these arguments talk about taxes, it's an indication of someone arguing backwards. Sorry, but CO2 doesn't care about who you vote for or how much tax you pay.