I was in Denmark last December when thousands of protesters showed their anger at governments and corporations, which continue to allow fear and greed to get in the way of solving this serious problem. There have been some small positive changes since then, but we're still far from a global agreement.
The main battle is between rich and poor nations. Developed countries want developing countries to share the burden of protecting the environment by switching to cleaner fuels and saving our forests.
Poor nations say the current global environmental crisis was caused by the rapid growth of developed countries such as the United States, Britain and France, and that they should pay for the clean-up.
Governments are still trying to agree on greenhouse gas reductions and who will police those cuts to make sure everyone is meeting their targets.
Just like in Copenhagen, there are hundreds of young people from around the globe at the meeting, trying to push leaders to make the right decision. The decisions being made will affect the future of today's teenagers, and their voices are important.
A group called the China-US Youth Climate Exchange is trying to encourage co-operation between governments, and is asking them to stop blaming each other for the mistakes and instead show some understanding and trust.
China and the US are the world's biggest emitters of greenhouse gas, but they disagree on what should be done. Understanding the challenges faced by both developing and developed countries is an important step to solving the problem.