July 05, 2007
Greenland Warmer Half Million Or So Years Ago

DNA samples found under a Greenland ice sheet suggest that Greenland was much warmer more recently than previously believed.

A team of international researchers has collected the oldest ever recovered DNA samples and used them to show that Greenland was much warmer at some point during the last Ice Age than most people have believed.

The ancient DNA was discovered at the bottom of a two kilometer thick ice sheet and came from the trees, plants and insects of a boreal forest estimated to be between 450,000 and 900,000 years-old. Previously, the youngest evidence of a boreal forest in Greenland was from 2.4 million years ago.

Natural trends will some day make Greenland much warmer than it is today.

Southern Greenland used to really be green.

The DNA samples suggest the temperature of the southern Greenland boreal forests 450,000 to 900,000 years-ago was probably between 10C in summer and -17C in winter. Also, the reduced glacier cover in that region means the global ocean was probably between one and two metres higher during that time compared to current levels.

One wonders whether the ability to recover such old DNA will enable the recreation of long lost species.

Researchers analysed ice cores from a number of locations in Greenland, including Dye 3 in the south of the country. From the base of the 2km deep Dye 3 core, they were able to extract what they believe is likely to be the oldest authenticated DNA obtained to date.

By analysing these DNA samples, the researchers identified a surprising variety of plant and insect life, including species of trees such as alder, spruce, pine and members of the yew family, as well as invertebrates related to beetles, flies, spiders, butterflies and moths. The researchers believe that the samples date back to between 450,000 and 800,000 years ago.

Suppose humanity still exists the next time natural trends cause a major warming of the planet. Should humans seek to prevent the natural warming? Suppose the natural warming will be greater than the human-caused warming that some climate models predict as a result of human burning of fossil fuels. Should we intervene to stop a natural trend that will cause rising ocean levels and expansion and contraction of many ecological niches? Should we seek to save the polar bear from extinction due to natural climate change?

Share |      Randall Parker, 2007 July 05 11:36 PM  Climate Trends

Botec said at July 6, 2007 1:33 AM:

I tell you, if there had been environmentalists around 380 million years ago, they'd have been racing down to the beaches to help the stranded lobe-finned fish back into the water.

Morpheum said at July 6, 2007 7:32 AM:

It's all about humans, it's just got to be! The earth can't make a move without human help, we all know that.

The GCM models have holes in them big enough to fly the space shuttle through. But they've got to be right, because they're so conveniently compatible with the message, you see.

Kurt9 said at July 6, 2007 8:11 AM:


Have a look at this:


The Earth is usually a lot warmer than it is now.

Brock said at July 6, 2007 10:07 AM:

Fascinating link. I wonder why the Earth seems to have two "stable states" at 12C and 22C...

Randall asks: "Should humans seek to prevent the natural warming?"

If it threatens our survival, yes. I don't believe in preserving "natural" conditions as an end in itself (if there even are such things), but I do believe in preserving conditions which are favorable to our specie's survival.

Randall asks: "Should we seek to save the polar bear from extinction due to natural climate change?"

If technological civilization is still around, the polar bear will be saved. It seems inevitable to me that small groups of polar bear fans will preserve their DNA and perhaps even keep a few live ones around in artificial habitats, regardless of what the rest of humanity thinks of the issue.

But it's a theoretical question anyway. By Kurt's time map link it looks like we're due for a flip to the 22C stable state "any minute now", but on that time scale it could be ten million years or more. By then it seems unlikely to me that "humans" (as we recognize them today) will exist at all. We'll either have evolved through self-inflicted genetic engineering or our technological civilization will have collapsed and we'll have evolved in a Darwinian fashion by then.

Hopefully Anonymous said at July 6, 2007 1:56 PM:

Brock, do you have an email contact? Anonymous is fine. I think we think very similarly on these topics and I agree with your post.

As to the OP, I think the question of whether we should intentionally interfere with "natural" climate change at the global level is an important question with utility beyond teasing global warming "alarmists" (scare quotes).

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