Recent proposed agreements among nations across the globe, brokered by the United Nations (UN), have provided some optimism in the human struggle to manage climate change. Talks over such arrangements are currently underway in Lima, Peru. However, according to some climatologists, the world cannot afford to wait for these proposals to be ratified and implemented.

Representatives from many nations are currently negotiating in South America and have expressed optimism for an international agreement to reduce fossil fuel emissions in a major coordinated effort to halt climate change. However, some believe that with the current rate of greenhouse gas emission and reasonable estimate of how long it would take between the proposal stage and actual beneficial effect of the new agreement, the world cannot afford to wait.

These scientists warn that a worldwide temperature increase of 3.6 degrees Fahrenheit will be impossible to prevent as things are currently progressing. They are leading the charge in pushing for more aggressive in reducing greenhouse gas emissions. Otherwise, the scientists warn, the planet will become increasingly unpleasant, economies will suffer, and the human race may ultimately die off.

Recently, U.S. President Barack Obama and China President Xi Jinping struck a deal to cut carbon emissions, an agreement that some say could end many years of failure in forming solutions to global warming in other nations.

“I was encouraged by the U.S.-China agreement,” Michael Oppenheimer, a professor of geosciences and international affairs at Princeton University and a member of the United Nations Intergovernmental Panel on Climate Change, said in an interview with a New York Times reporter.

Oppenheimer noted, however, that current emission trends mean that it is already too late to prevent a temperature increase.

“What’s already baked in are substantial changes to ecosystems, large-scale transformations,” Oppenheimer said, adding that without a deal struck in Lima, “things could get a lot worse.”