David Cameron has said the world must take action on climate change now before it is too late.
Addressing a summit in Paris, the Prime Minister said: "Instead of making excuses tomorrow to our children and grandchildren, we should be taking action against climate change today.
"What we are looking at is not difficult, it's doable, so therefore we should come together and do it."
Barack Obama's greatest struggle on climate change could be convincing the conspiracy theorists at home that it's not a hoax.
People across the globe have posed their questions for President Obama as he takes part in the UN Climate Conference in Paris.
The Prince of Wales said world companies 'pay no attention' to the damage their supply chains cause to forests.