The Paris Climate Pact Is in Effect, but It’s Not Enough

Less than a year after its inception, the Paris climate change agreement is officially in force—but the United Nations has warned that governments must dramatically reduce carbon emissions to meet its goals.

The agreement, drawn up last December, was formally ratified by enough nation-states last month. As of November 4, it’s binding for the countries that decided to sign up, which includes the U.S., China, and the members of the EU. Those countries must now endeavor to reduce their fossil-fuel use in order to limit average global temperature rises to less than 2 °C above preindustrial levels.

“This is a moment to celebrate,” said the United Nations’ climate chief Patricia Espinosa in a statement. She’s right: such large-scale international agreements are notoriously difficult to engineer. While negotiations were painful, the agreement is a beacon of hope for humankind, signaling that efforts will be made to mitigate the effects of climate change.

But Espinosa also warned that now is not a time for complacency. “It is also a moment to look ahead with sober assessment and renewed will over the task ahead,” she said. “In a short time … we need to see unprecedented reductions in greenhouse gas emissions and unequaled efforts to build societies that can resist rising climate impacts.”

In fact, a new UN report warns that the emissions pledges put forward by the countries to date don’t go far enough. It suggests that the emissions targets between now and 2030 will actually put the world on track to warm 3.4 °C by 2100. The report says that a further 25 percent reduction in emissions will be required to keep warming below 2 °C.

If officials seek a visceral reminder of how big an impact carbon dioxide emissions have on the planet, they have one in the shape of a new study published in Science about the impact of the gas on Arctic ice. Calculations suggest that three square meters of ice are lost for every ton of carbon dioxide emitted. That means the addition of another 1,000 gigatons of carbon dioxide into the atmosphere—about the amount that can be emitted before temperature rises exceed 2 °C—would render the Arctic ice-free during the summer.

As Espinosa says, the Paris agreement is good news. But we’re still a long way from where we need to be.

(Read more: Reuters, UN (PDF), Science, “The Paris Climate Pact Is Officially Go,” “Paris Climate Agreement Rests on Shaky Technological Foundations”)