Politicians and activists from over 100 countries are about to descend on Qatar to discuss plans to slow climate change - but their journey there will leave a huge carbon footprint. Meanwhile in Costa Rica, students at the Earth University are working on climate-neutral technologies - and in Germany, organic potato farmers are increasingly incensed by their Egyptian competitors.
How can the world curb climate change? The first step is to cut carbon emissions by at least 25 percent.
In order to make this target official, politicians and environmental activists are coming together for another UN Climate Change Conference - this time in Doha, Qatar. Getting them all there, however, will leave a serious carbon footprint.
Costa Rica has set itself the ambitious target of becoming carbon-neutral by 2021. Much of the research required to ensure that this target is met is being carried out at the Earth University. Here, students are exploring clean energy solutions as well as sustainable agriculture and waste management strategies.
The country still has a long way to go. Until well into the 1980s logging was widespread in Costa Rica, with 75 percent of its rainforest destroyed to make way for cattle pastures.
A few years ago, what's thought to be the world's largest coal deposits were discovered in north-western Mozambique. Tete Province is sitting on billions of tonnes of coal reserves. The discovery has transformed the region.
The prospect of reaping huge profits has led some of the world's biggest multinational mining companies to invest billions here. But is the local population benefiting from the boom?
This time we meet Kuy Savan, a security guard at an Internet gaming store in Phnom Penh, the capital of Cambodia.
Buying organic means helping the environment. But there are no set standards for organic food production around the world and working conditions vary enormously from country to country.
Organic potato production in Germany, for example, differs substantially from organic potato farming in Egypt. And German farmers are questioning the ecological sense of importing spuds from foreign countries when they can just as easily be grown at home.