Don't be a denialist - global warming has happened before and is happening now.Look at the CO2 chart. It is very likely that the level of CO2 in the atmosphere is greater now than at anytime since the advent of the human species as we know it. And we know unequivocally that the more the CO2, the warmer the planet.
Yes, greenhouse gas global warming has happened before . . . but not since the human species has been around. One of the most notable episodes occured 55 million years ago, (that's 53 million years before humans evolved to our present state). This warming event, called the Paleocene-Eocene Thermal Maximum (PETM), upset oceanic and atmospheric circulation, leading to the extinction of a great number of species. This event affected species evolution causing a major turnover in mammalian life on land, marking the emergence of mammalian species lines recognizable today. Sea surface temperatures rose between 5 and 8°C over a period of a few thousand years, and in the high Arctic, sea surface temperatures rose to a sub-tropical 23°C/73°F. Causes for this warming have been attributed to the release of methane in the atmosphere. The melting of methane 'ice' that forms in cold water under great pressure caused a massive release of sedimentary methane hydrates into the ocean & atmosphere. Methane was rapidly converted to carbon dioxide in the atmosphere, upsetting the global carbon cycle which led to runaway global warming. Volcanic activity may have been a factor and some suggest a massive asteroid or comet impact could have also triggered the episode.
How do they know and what can we learn from this?
Scientists studying core samples drilled into the ocean floor have been able to determine what life existed in various places such as the Arctic and elsewhere. Scientists discovered the remains of tiny algae called Apectodinium in the Arctic, which previously had been restricted to warmer regions of the world. The presence of Apectodinium during the Paleocene-Eocene Thermal Maximum confirms subtropical conditions existed in the Arctic during this time. Sediment cores drilled from the ocean floor revealed an abrupt change in ocean chemistry at the start of the PETM 55 million years ago, followed by a recovery that took at least 80,000 years. Through this research, the link between advancing levels of atmospheric CO2 and rising air and ocean temperatures has been undoutedly established.
Global warming then was ultimately the result of higher carbon dioxide concentrations, as the released methane would have been rapidly converted to carbon dioxide in the atmosphere.
The same thing is happening now
8 scientific climate model projections are in relative agreement, this global warming event is extraordinary - likely as dramatic or more so than the PETM episode 55 million years ago that caused mass extinctions. The 8 models, representing the best science available predict the sea surface temperature will rise between 2 and 3.8°C in the next hundred years. The PETM was said to have been the result of a 5 to 8°C sea surface temperature rise over a few thousand years. The present trend would clearly indicate an event like the PETM is a likely possibility.
So what?
Yea, so what, we'll all be dead by the time these drastic effects impact most humans. Just forget about politics. Forget about what Al Gore says, what the 'Bushcult 30%ers' tell you. Just look at the science.
Forget about causes and remedies and politics.
Just look at the science and the data.
More on the politics of all this in a later post.
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