Bryozoans found in the Ross and Weddell seas were almost identical, meaning the ice sheet that separates them isn’t as ancient as once thought. Photograph: British Antarctic Survey

But in recent years the vegetation around his home, the Tibetan plateau, has been destroyed by rising temperatures, excess livestock and plagues of insects and rodents.

The high-altitude meadows are rarely mentioned in discussions of global warming, but the changes to this ground have a profound impact on Tibetan politics and the world’s ecological security.

For Phuntsok Dorje, the issue is more down to earth. He is used to dramatically shifting cloudscapes above his head, but it is the changes below his feet that make him uneasy.

“The grass used to be up to here,” Phuntsok says, indicating a point on his leg a little below the knee. “Twenty years ago, we had to scythe it down. But now, well, you can see for yourself. It’s so short it looks like moss.”

The green prairie that used to surround his tent has become a brown desert. All that is left of the grasslands here are yellowing blotches on a stony surface riddled with rodent holes.

It is the same across much of this plateau, which encompasses an area a third of the size of the US.

Desertification

Scientists say the desertification of the mountain grasslands is accelerating climate change. Without its thatch the roof of the world is less able to absorb moisture and more likely to radiate heat.

Partly because of this the Tibetan mountains have warmed two to three times faster than the global average; the permafrost and glaciers of the “Third Pole” are melting.

To make matters worse, the towering Kunlun, Himalayan and Karakorum ranges that surround the plateau act as a chimney for water vapour – which has a stronger greenhouse gas effect than carbon dioxide – to be convected high into the stratosphere. Mixed with pollution, dust and black carbon (soot) from India and elsewhere, this spreads a brown cloud across swaths of the Eurasian landmass. When permafrost melts it can also release methane, another powerful greenhouse gas. Xiao Ziniu, the director general of the Beijing climate centre, says Tibet‘s climate is the most sensitive in Asia and influences the globe.

These days, it’s hard to have inspiring Mr Chips moments when you teach climate change policy. My students at least seem increasingly demoralised by the tepid and technical nature of most climate debate. Which is probably why they recently challenged me to offer a proposal that was not only workable but game-changing. That’s a challenge even Mr Chips would struggle to meet, but here’s an attempt anyway: what if we could use the cap-and-trade system to reshape politics at the same time that we reduce greenhouse gas emissions? We can, if we move from carbon offsets to carbon upsets.

Last year, in a little noticed case, environmental groups and the United States government reached a settlement that will dramatically lessen future greenhouse gas emissions. The Overseas Private Investment Corporation and the Export-Import Bank of the US agreed to change the way they evaluate the climate impact of funded projects. But the groups that won the settlement received no credit – literally – and that’s a problem.

Contrast that story with “carbon offset” projects, which receive greenhouse gas reduction credits through some official process like the Kyoto Protocol’s Clean Development Mechanism (CDM). These financial instruments can be so lucrative that firms actually raise production levels solely to create more pollution which they might then reduce. If that sounds crazy, it should.

In theory, carbon offsets are a way to lower the cost of emissions reductions. Credits are awarded when a project is less greenhouse gas-intensive than it would have been in the usual course. These credits can then be sold to polluters and used to satisfy their emissions reduction obligations which would have been more expensive to undertake directly. In practice critics have pointed to numerous problems with offsets. Most fundamentally, they fail to incentivise the kind of structural transformation toward a low-carbon future that we desperately need.

Here’s where “carbon upsets” come in: Rather than award credits based on development that moves us toward a cleaner but still very dirty future, why not award credits to legal and political actions that have more dramatic impact? For instance, rather than bribe fossil fuel companies to stop flaring natural gas, why not reward indigenous groups that entirely block new exploration activities? Rather than transfer money to logging operations for incremental replanting programs, why not award credits to forest-dwelling communities that successfully fight to stop logging altogether?