President Barack Obama and other White House officials are in Paris this week attending the 2015 United Nations Climate Change Conference. The two-week event is meant to bring countries together to discuss strategies for combating climate change and preventing the global temperature from rising by more than 2 degrees Celsius above the average pre-Industrial Revolution temperature. That number is the threshold at which most scientists agree the effects of climate change would significantly alter the planet and lead to devastating consequences for the world’s population. The planet is currently on course to hit that mark by mid-century.

Prior to the summit, all countries were asked to develop voluntary pledges detailing how they would aid the global fight against climate change; more than 150 nations have already submitted national plans to the United Nations, the United States included. Some pledges detail plans to cut greenhouse gas emissions, while others will preserve forest cover or use more clean energy.

If all goes as planned, the summit will produce a global, legally binding agreement to curb climate change. The pledges already submitted to the United Nations are estimated to reduce the planet’s currently projected warming of 4.5 degrees Celsius to about 2.7 to 3.7 degrees. The Paris summit is not expected to produce a plan that avoids the 2 degrees Celsius threshold, but instead require countries to make increasingly ambitious efforts to combat climate change, and thereby meet the target over time.

President Obama was optimistic following the first day of the talks, stating in a news conference “I actually think we’re going to solve this thing.”