We’ve spent a nice 10,000 years enjoying quite a cozy epoch, one that has nurtured human evolution and provided us with large habitable regions in which to develop our bustling civilizations. The degree of climate change we are facing, however, could push us into an entirely foreign set of climate conditions quite soon, a recent paper concludes. The crux of the paper, which is based on research on ice cores and other paleoclimate records, is that the Earth’s climate system hasn’t responded fully yet to the rapid increase in greenhouse gases in the atmosphere, and that much more warming is in the pipeline for the damage already done. In other words, the changes could be so dramatic that the Earth will likely leave the climate of the Holocene era soon.

This geological epoch began around 8,000 BCE and coincided with the rise of agriculture and the domestication of farm animals; some scientists are suggesting we may have already entered the Anthropocene-- the "era of man." What the end of the Holocene end would mean for humanity — the net effect of the rapid diminishing of species diversity, the loss of ice, and more — is, of course, very uncertain by virtue of the fact that there is no precedent for it in human existence.

The lead author of the paper, published in the Open Atmospheric Science Journal, is James Hansen, a climate scientist at the NASA Goddard Institute for Space Studies who was thrust into the spotlight over his claims that the government space agency attempted to censor or control his public statements on climate change (claims largely substantiated by reporters and government investigators). He has criticized the Bush administration of repeatedly playing down the risk of climate change. Hansen has said in the past that the world might be approaching a climate tipping point as early as 2016, where only moderate increases in greenhouse gases can lead to serious global shifts through feedback loops in the climate system.

This paper again addresses near-term tipping points and threatens that just one more decade of growing greenhouse gas emissions would make it practically impossible to stabilize atmospheric conditions beneath a tipping point. The authors suggest that the only way to sharply pull back on CO2 emissions would be to eliminate emissions from coal, either by phasing out its use or requiring carbon capture and sequestration for every coal plant.

Reshaping the landscape

Even apart from the stunning species extinctions currently underway — at a rate unseen in the last 65,000,000 years -— some dramatic changes are already beginning to reshape the landscape of human life. In March 2009, for example, the world’s first climate-change refugees will leave their homes for a nearby Papua New Guinean island. The migration is the first wave of Carteret Island natives to abandon the atoll in response to steadily rising sea levels, which are expected to fully submerge the place by 2015.

And the Carterets aren’t the only ones warily eyeing their shorelines. So are the residents of the Maldives, an island nation that recently underwent its own dramatic shake-up of the political scene. The country’s first democratically elected president takes power tomorrow, and he has real estate very much on the mind. Mohamed Nasheed told the UK Guardian that he will begin diverting tourism revenue towards buying a new homeland as an “insurance policy” against climate change. The highest point on the Maldives is less than three meters above sea level, so his caution isn’t an over-reaction. The 300,000 residents may eventually relocate to India, Sri Lanka, or Australia, Nasheed says.

Story by Sandra Upson. This article appeared in Plenty in November 2008 and was purchased and published on MNN in 2009.

The end of the Holocene?
Say goodbye to the last 10,000 years.