April 28, 2013
Earth Cooling Trend Reversed Around 1900 AD?
The industrial revolutionaries were accidental climate engineers too?
A reconstruction of 2,000 years of global temperatures shows that a long-term decline in Earth's temperatures ended abruptly about 1900, replaced by a warming trend that has continued despite the persistence into the 20th century of the factors driving the cooling, according to a new study.
The more interesting thing about this report isn't that humans humans are probably causing rising temperatures by causing so much CO2 emissions. That already seems pretty likely. What is more interesting: the long term cooling trend could mean we were headed for another ice age. Maybe only the industrial revolution prevented it. So suppose humans developed more slowly in the industrial revolution was delayed by hundreds of years. Would it have happened at all? Or would the human population have dived before it had a chance to get going?
So the question arises: What's the ideal climate for the planet? Different people will have different answers depending on where they live. This isn't just about how cold is winter or how hot is summer. Though at globally 5C warmer some US states would become very undesirable and even dangerous places to live. What else matters: rain distribution. Raise temperatures a few degrees C and watch some now habitable places become deserts while other places get more rain.
A highly industrialized nation with cheap energy has lots of options for ameliorating the effects of climate change. Suppose a massive decades long drought hits the Canadian and American plains. Then imagine either a big fusion energy breakthrough or a large continuing decline in solar energy costs.Pump in massive amounts of desalinated water from the coasts. Dump some of it in Montana and Alberta into dams. Some will evaporate for local and regional rains. The Missouri and other rivers could carry the water into parched plains states. Poor nations would not have that option.
Randall Parker, 2013 April 28 05:30 PM
And then there's the Fallen Angels scenario, where we actually do accede to the demands of those worried about global warming, and end up with an ice age on our hands.
A great deal of effort has been put into proving the existence of global warming. That the optimum global temperature isn't higher than the present has, for the most part, simply been assumed.
Well, I'm certain that "colder" is not better.
Regardless of the optimum, it's certain that neither wildlife nor crop plants nor humanity itself evolved under conditions warmer than the most recent interglacial maximum.
EP, The surviving flora and fauna, yes, they evolved in cold climates, then the population of most exploded when the inter-glacial started.
Consider the enormous human population today. What would happen if glaciation returned?
Habitable land would disappear in the north, shoving human population south into unsupportable concentrations. The Han Empire (Red China) would swamp SE Asia, Indonesia, Philippines, Australia, and NZ, massacring locals, Han or not. Canada would vanish as a nation, the US would have to annex northern Mexico (which would become more fertile due to weather shifts). South America might survive, with "adjustments", likewise many of the African nations. Or they could, if not for probable influx of huge numbers of people from the US, Europe, and Russia.
I'd expect the human population to stabilize around 5% of today, survival of the most ruthless canabiles. Any animal large enough to be worth tossing in the soup pot would become extinct. Any plant requiring soil that might possibly grow food would become extinct as the soil is pre-empted for crops.
I find that rather improbable, it would require the glaciation to return on a rather fast schedule. Humanity has the technological power to reverse glaciation if it proves necessary, by a variety of means ranging from covering glaciers with soot, to redirecting solar radiation with large mirrors. Little is being done in response to the warnings of the global warming movement, but that's generally due to the low level of proof provided that warming is actually a threat. Glaciers advancing to cover farm land is a pretty darned obvious threat.
"Glaciation" was a shortcut. The cold weather that creates glaciers is the problem as it also reduces the growing period and soil temperature required by many crops. The crop problem precedes the glaciers.