Pre-coal anthropogenic climate factors were localized and small in comparison with today. Deforestation was mainly it and solar variation was a larger effect than human burning and deforestation. In America, the introduction of horses led to easier taking of animals and migrations for tribes. Tribes who sometimes used prairie and forest fires to get game, or move them to a kill point. Mountain men took beavers to near extinction until felt was no longer in style, and other animal furs until more wool and cotton were produced. Early settlers , and later ones , too, deforested vast tracts.
The post coal industrial revolution it drove was the beginning of a stimulated human population with steamships able to bring food to places where they couldn't before and in new types of food. Then oil was discovered and it increased more. For at least 1.1 million years the atmospheric CO2 varied, usually sedately, between 180 and 280 ppm. There were no exact measurements of it then, but it was estimated to be near the high side at 275ppm at the start of human geometrically increasing HGHGs, now just over 395 ppm and 400 ppm in the Arctic, triggering tundra methane releases rising geometrically.
Before fossil fuels, the deforestation rate was small, but now we have cut down or burned 57% of rainforests. The US is down to about 1% of old growth forests. Pre coal, the rainforests and oceanic phytoplankton absorbed variations in CO2, and provided over 80% of the Earth's oxygen. Now, CO2 acidification of the oceans has killed off 40% of the phytoplankton.
Many human tribes were not gentle on the biosphere before coal. Some had stewardship in their religions or philosophies. When the former discovered coal and oil, they couldn't think like the others and use this resource at its natural regeneration rate, and didn't really try to know it at first. The others had the wisdom passed down by elders to guide them in sustainability.
Pre-coal, natural forces on climate far outweighed human effects. When it was colder, humans burned more and took more furs, but it was still within the planetary absorption ability. This all ended some time after fossil fuels became widely burned and geometric population growth started.
In the past, the Sahara was a savanna with many rivers. Natural climate change brought an end to it and people adapted or migrated. People adapted during the last ice age and migrated first over water to the Americas, following the oceanic ice edge. Before that in the south where it was still warm, they traveled over exposed land and used boats and rafts for voyages to other lands in sight, like Australia. During the previous interglacial they first left Africa when it was warm elsewhere on land. The development of tools and clothes gave them more success with variable climate in the temperate zone.
Rats followed humans for food scraps(later grain stocks), along with cats and dogs who became friendly and controlled the rats.
Found this from 2005 of interest:
"The scientific consensus that human actions first began to have a warming effect on the earth's climate within the past century has become part of the public perception as well. With the advent of coal-burning factories and power plants, industrial societies began releasing carbon dioxide (CO2) and other greenhouse gases into the air. Later, motor vehicles added to such emissions. In this scenario, those of us who have lived during the industrial era are responsible not only for the gas buildup in the atmosphere but also for at least part of the accompanying global warming trend. Now, though, it seems our ancient agrarian ancestors may have begun adding these gases to the atmosphere many millennia ago, thereby altering the earth's climate long before anyone thought.
New(2005) evidence suggests that concentrations of CO2 started rising about 8,000 years ago, even though natural trends indicate they should have been dropping. Some 3,000 years later the same thing happened to methane, another heat-trapping gas. The consequences of these surprising rises have been profound. Without them, current temperatures in northern parts of North America and Europe would be cooler by three to four degrees Celsius--enough to make agriculture difficult. In addition, an incipient ice age--marked by the appearance of small ice caps--would probably have begun several thousand years ago in parts of northeastern Canada. Instead the earth's climate has remained relatively warm and stable in recent millennia." From Scientific American archives.
screw snow the denialist maniac, may he rot in hell for his delay tactics toward emissions reductions.
http://dieoff.org/peruse, my dear
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