Don’t burn all the fossil fuels (yet)

Tom James @ 19-02-2009

icebergAccording to Professor Gary Shaffer of the University of Copenhagen we should stop burning fossil fuels now so that we will have enough coal, oil, and gas left when we need to fend off the next ice age over the next several hundred thousand years:

…for a management scenario whereby fossil fuel use was reduced globally by 20% in 2020 and 60% in 2050 (compared to 1990 levels), maximum global warming was less than one degree Celsius above present. Similar reductions in fossil fuel use have been proposed by various countries like Germany and Great Britain.

In this scenario, combustion pulses of large remaining fossil fuel reserves were then tailored to raise atmospheric CO2 content high and long enough to parry forcing of ice age onsets by summer radiation minima as long as possible. In this way our present equable interglacial climate was extended for about 500,000 years, three times as long as in the “business as usual” case.

Nice to see some people are cranking up their Buxton indices into the 100, 000 years range.

[via FuturePundit][image from nick  russill on flickr]


Global warming argy bargy

Tom James @ 12-11-2008

A study suggests that long-term changes in the Earth’s orbit would have resulted in an ice age between 10,000 and 100,000 from now, if it were not for the effect of anthropogenic global warming:

The chill would induce a long, stable period of glaciation in the mid-latitudes, smothering Europe, Asia and North America to about 45-50 degrees latitude with a thick sheet of ice.

However, there is now so much CO2 in the air, as a result of fossil-fuel burning and deforestation, that this adds a heat-trapping greenhouse effect that will offset the cooling impacts of orbital shift, said Crowley.

“Even the level that we have there now is more than sufficient to reach that critical state seen in the model,” he said. “If we cut back [on CO2] some, that would probably still be enough.

Apparently this isn’t an excuse to continue venting CO2:

Crowley cautioned those who would seize on the new study to say “‘carbon dioxide is now good, it prevents us from walking the plank into this deep glaciation’.”

“We don’t want to give people that impression,” he said. “(…) You can’t use this argument to justify [man-made] global warming.”

[story at Physorg][image from Pear Biter on flickr]


Climate change all over the place

Tom James @ 06-11-2008

And speaking of climate change there is an interesting story at the BBC about how monsoons/droughts, as recorded in the concentrations of minerals in stalactites, have been linked with Chinese dynasties:

By comparing the rain record with Chinese historical records, Pingzhong Zhang of Lanzhou University in China, and colleagues, found three out of five “multi-century” dynasties – the Tang, the Yuan and the Ming – ended after several decades of weaker summer monsoons with drier conditions.

These moisture-laden winds bring rain necessary for cultivating rice. But when the monsoon is weak, the rains stall farther south and east, depriving northern and western parts of China of summer rains.

This could have led to poor rice harvests and civil unrest, the researchers speculate.

It’s an interesting theory, and reflects how important climate is in the lives of humanity, and also in the lives of lemmings, with the discovery that the lemming population of Norway is no longer as fecund as it once was:

The research team, composed of Norwegian and French scientists, believes the winters are now too humid, leading to the “wrong kind of snow“.

This results in a less stable subnivean space (the space between the ground and the snow layer above), meaning substantially fewer animals survive until spring.

Aww. But apparently it’s not all bad news vis a vis climate change. Apparently certain Alaskan glaciers have in fact grown this year for the first time in 200 years.

This will please Sarah Palin – who apparently has only recently discovered that Africa is a continent, not a country.

Congrats on the win, America!

As to the glaciers – only time will tell.

[wanxiang cave image from BBC News, lemming from kdleditsch on flickr]