Environment Exts - Warming Bad - Anthropogenic

Environment Exts - Warming Brinks

We are getting close to the point of no return - earth will soon be at a point that natural feedbacks will make warming irreversible and unstoppable

There have been five mass extinctions in the past 500 million years, when 50 percent or more of the species then existing on the Earth vanished, but until recently the only people taking any interest in this were paleontologists, not climate scientists. They did wonder what had caused the extinctions, but the best answer they could come up was "climate change." It wasn't a very good answer.

Why would a warmer or colder planet kill off all those species? The warming was caused by massive volcanic eruptions dumping huge quantities of carbon dioxide in the atmosphere for tens of thousands of years. But it was very gradual, and the animals and plants had plenty of time to migrate to climatic zones that still suited them.

There had to be a more convincing kill mechanism than that, and the paleontologists found one when they discovered that a giant asteroid struck the planet 65 million years ago, just at the time when the dinosaurs died out in the most recent of the great extinctions. So they went looking for evidence of huge asteroid strikes at the time of the other extinction events. They found none.

What they discovered was that there was indeed major warming at the time of all the other extinctions -- and that the warming had radically changed the oceans. The currents that carry oxygen-rich cold water down to the depths shifted so that they were bringing down oxygen-poor warm water instead, and gradually the depths of the oceans became anoxic: The deep waters no longer had any oxygen.

When that happens, the sulfur bacteria that normally live in the silt (because oxygen is poison to them) come out of hiding and begin to multiply. Eventually they rise all the way to the surface over the whole ocean, killing all the oxygen-breathing life. The ocean also starts emitting enormous amounts of lethal hydrogen sulfide gas that destroy the ozone layer and directly poison land-dwelling species. This has happened many times in the Earth's history.

Don't let it worry you. We'll all be safely dead long before it could happen again: The earliest possible date for a mass extinction, assuming that the theory is right and that we continue down our present track with emissions, would be well into the next century.

The only problem is that things like this tend to become inevitable long before they actually happen. Tick, tock.

Environment Exts - Warming Impacts - Laundry List

Unchecked climate change leads to every major impact - famine, drought, resource wars, ecological devastation and nuclear war

But the real importance of the report lies in the statement of probability and in the authors' recommendations to the President and the National Security Council. While no statistical analysis of probability is given in the report as it has been released (any such statistical analysis would most likely be classified), the authors state that “the plausibility of severe and rapid climate change is higher than most of the scientific community and perhaps all of the political community is prepared for.”6 They say that instead of asking whether this could happen, we should be asking when this will happen. They conclude: “It is quite plausible that within a decade the evidence of an imminent abrupt climate shift may become clear and reliable.”7 From such a shift, the report claims, utterly appalling ecological consequences would follow. Europe and Eastern North America would plunge into a mini-ice age, with weather patterns resembling present day Siberia. Violent storms could wreak havoc around the globe. Coastal areas such as The Netherlands, New York, and the West coast of North America could become uninhabitable, while most island nations could be completely submerged. Lowlands like Bangladesh could be permanently swamped. While flooding would become the rule along coastlines, mega-droughts could destroy the world's breadbaskets. The dust bowl could return to America's Midwest. Famine and drought would result in a major drop in the planet's ability to sustain the present human population. Access to water could become a major battleground – hundreds of millions could die as a result of famine and resource wars. More than 400 million people in subtropical regions will be put at grave risk. There would be mass migrations of climate refugees, particularly to southern Europe and North America. Nuclear arms proliferation in conjunction with resource wars could very well lead to nuclear wars.8 And none of this takes into account the effects of global peak oil and the North American natural gas cliff. Not pretty.