Without drastic efforts to reduce deforestation, rising greenhouse gases, and unsustainable global agriculture, the planet is on track to lose a massive quantity of its tropical forests—a crucial element in the fight against irreversible climate change—in just 35 years.

Absent aggressive conservation policies, the world will lose 2.9 million square kilometers of its tropical forests by 2050, according to a new working paper published Monday by Center for Global Development (CGD) environmental expert Jonah Busch and research assistant Jens Engelmann. That’s a chunk the size of India, or one-third of U.S. land mass.

And if no changes are made to the world’s “business-as-usual” approach to agriculture, logging, and other such forces, tropical deforestation will account for more than one-sixth of the remaining carbon that can be emitted if the world is to limit global warming to 2 degrees Celsius.

The carbon emissions that would occur during that process would add up to 169 billion tons—the equivalent of running 44,000 typical coal plants per year, Busch explained in a blog post accompanying the report, entitled The Future of Forests: Emissions from Tropical Deforestation with and without a Carbon Price, 2016–2050 (pdf).

According to a separate study published earlier this year by NASA, tropical forests are absorbing carbon dioxide at a far higher rate than previously thought, making them an invaluable resource in curbing global warming.

That’s the bad news. The good news, Busch writes, is that there are many solutions available.

“Avoiding dangerous climate change while expanding economic prosperity is perhaps the defining challenge of the 21st century,” Busch writes. “Achieving both goals requires reducing greenhouse gas emissions where doing so has the lowest unit cost.”

Carbon pricing is one example. Applying a global fee of $20 per ton of carbon dioxide between 2016 and 2050 would keep 41 gigatons of emissions from being discharged, the researchers found.

Another option is to follow Brazil’s model of targeting greenhouse gases, which involves “satellite monitoring, law enforcement, new protected areas and indigenous territories, restrictions on rural credit, and moratoriums on unsustainable soy and cattle production,” Busch writes. “As a result of these restrictive measures, Amazon deforestation fell by nearly 80 percent since 2004 even while Brazil’s soy and cattle production increased.”