(Editor’s Note: Earthjustice attorneys Martin Wagner and Erika Rosenthal are blogging from the United Nations climate conference in Cancun, Mexico.)

"I was born in 1992. You have been negotiating all my life. You cannot tell me that you need more time."

This is the text on the t-shirts worn today by each of the international youth delegates here at the United Nations climate change negotiations in Cancun. It comes from a speech that Christina Ora of the Solomon Islands gave at last year’s negotiations in Copenhagen.

Christina has a point.

The basic U.N. climate change treaty was produced in 1992 (the first President Bush ratified the agreement on behalf of the United States the same year). Ever since, the members governments have engaged in essentially continuous negotiations to establish and strengthen commitments that could avoid catastrophic climate change. And as the negotiations have dragged on, the evidence of the need for progress has grown.

 I was reminded of the cost of delay again this evening at a presentation about a report authored by more than 30 leading scientists from numerous international research institutions. These scientists have examined the most recent scientific data to determine what needs to happen to avoid increasing global temperatures so much that we kick the planet into irreversible climate change. One of the clear lessons of this research is that the longer we delay in cutting greenhouse gas pollution, the less likely we can avoid catastrophe.

But the primary purpose of the study was to determine whether current emissions reductions promised by governments can keep global temperatures within a manageable range. The conclusion: not a chance.

Under the best case scenario—meaning that governments fully implement everything they’ve promised and it all works out the way they hope—the scientists found that emissions would overshoot the safe annual limit by 5 gigatonnes of carbon dioxide in 2020, the amount emitted each year by every car, truck and bus in the world. More likely scenarios overshot by twice that amount.

But even this stark warning hasn’t motivated the key governments to act more quickly. The U.S. and China are locked in a battle over who has offered the most and who should take the next step, with the United States effectively handcuffed by climate deniers and fossil fuel interests in Congress. Other important countries are using this impasse to justify their own inaction.

So when the facts cannot change minds, it falls to people like Christina Ora to create changes of heart. I have written before about the power of the youth delegations at these negotiations. As in past years, they are here in force. And they are not just here to watch, they are participating in whatever way they can. Today, I needed to get a proposal for improved treaty language to a Norwegian government negotiator. A Norwegian youth delegate offered to find the right person and put us in touch, and then she did it. Other youth are doing anything they can, from taking notes at strategy meetings to participating in discussions with UN officials.

For me, though, it is their simple presence here that is most moving. By being here – in the halls, in the negotiating rooms, on the streets—they are a constant reminder of what is at stake: not just our own world, but that of our children and their grandchildren, for as far into the future as we can imagine.

We do not need more time, Christina. The time is now.