It's been a big week for the planet. Yesterday, the world’s biggest polluter, China, said it would slow the rampant growth of its carbon emissions. This week President Obama voiced his own proposal: a committment to cut U.S. greenhouse gas emissions in several stages. BBC environment correspondent Matt McGrath joins us to make sense of these announcements - what do they mean for a hypothetical international climate change deal in Copenhagen?

Science's journey into the future is being delayed. A global attempt to create nuclear fusion is being threatened by rising costs and technical challenges. The ITER project was set up in 2006 by the U.S. and other countries to build an experimental nuclear fusion reactor in the south of France. But the weak economy might mean that fusion as a source of commercial power is at least a hundred years away. BBC science correspondent Matt McGrath joins us with more.

For an explanation of nuclear fusion, watch the video below.

President Obama is set to announce today new fuel efficiency standards for American cars. For the first time ever, auto manufacturers will have to meet a national standard. According to the Obama administration, the standards will be the equivalent of taking 177 million cars off the road by 2016. So what is the new standard and how does it compare with other countries are doing? We turn to Matt McGrath, the BBC's environment correspondent.

The World Health Organization has raised its pandemic threat level to Phase Five. What does that mean? The BBC's Matt McGrath explains the connection between the threat level and international caution.

Click through for a transcript.

As the confirmed numbers of confirmed cases of swine flu continue to rise around the world, countries are responding at their borders, tightening transport and immigration controls. Joining us now to look at how the world is responding at the border is BBC Correspondent Matt McGrath.

Here's the AP's report on how the swine flu is sparking border precautions:

It's a common assumption that plants grow best in clear sunny weather, but scientists say this isn't always the case. Research has shown that forests and crops can also thrive in hazy conditions because clouds and particles, that's right, pollution, in the atmosphere scatter sun light so that it bathes more leaves, enhancing photosynthesis, the process by which plants turn light and carbon dioxide into food. All this pollution we humans have created has dimmed the skies and this so-called global dimming actually increased plant productivity (in the photosynthetic way) by as much as a quarter from 1960 to 1999. That amounts to more than a ten percent increase in carbon dioxide storage, which is good! To help us see through the smog, Matt McGrath, BBC Science Correspondent, joins The Takeaway with this report.

At a science conference in Copenhagen this week, there's a "last call" for scientists who want to present evidence in the case for global warming. American, British and other European scientists will present latest scientific findings on climate change since the IPCC (Intergovernmental Panel on Climate Change) report in 2007. This is in part an attempt to encourage an international climate treaty in December in Copenhagen. Joining The Takeaway from Copenhagen is BBC Environmental Correspondent Matt McGrath.

One topic being addressed at the conference is rising sea levels. Watch the video below for more information.

But will the economic slowdown hamper environmental progress?