Carbon pollution is a direct cause of global climate change. This is a simple, scientific fact -- a fact that compels us to act.

The threats posed by climate change are real. We already feel the impact in our coastal communities. We feel it in more dangerous storms and spreading droughts. Scientists warn that this is only the beginning -- that if we fail to act now, the world as we know it will change dramatically for the worse.

On Monday, President Barack Obama took the latest and most ambitious step by any American administration to meet our responsibilities to protect the climate. The Environmental Protection Agency for the first time proposed limits on carbon emissions from power plants that have been polluting for decades.

Once finalised, these limits alone will reduce U.S. power sector emissions by as much as 30 per cent by 2030. They will avoid up to 6,500 premature deaths and prevent 150,000 asthma attacks in children each year, according to EPA calculations.

Over the past five years, domestically and with our international partners, the U.S. has done more to reduce the threat of climate change than in the two previous decades. Today, thanks to President Obama’s climate action plan, the U.S. is well on the way to meeting our international commitment to cut our greenhouse gas emissions by 2020.

That progress has occurred because we are going straight to the largest sources. We have been targeting emissions that come from our cars, trucks and power plants -- which together account for more than 60 per cent of the greenhouse gases that are destroying our climate.

At the same time, Americans have doubled the amount of energy that we are generating from wind and solar sources, and have become smarter about the way we use energy in our homes and businesses. As a result, today we are emitting less than we have in nearly two decades.

But even as we strive to do better, we recognise that no country can solve this problem alone. Even if the U.S. somehow eliminated all our domestic greenhouse gas emissions, it still would not be enough. The rest of the world is spewing too much carbon pollution. Indeed, if even a few key economies fail to respond to this threat, the world will be unable to cut carbon pollution enough to safeguard our environment.

Global co-operation is required. Industrialised countries have to play a leadership role in reducing emissions, but that does not mean other nations have the right to repeat the mistakes of the past.

When big nations including the U.S. were industrialising, we did not know the environmental impact that would come as a result, nor did we have better alternatives. Today, the world has alternatives -- the question is not whether to grow, but how. And today, we understand that emissions coming from anywhere threaten the future for people everywhere.

The U.S. is prepared to play a leading role, both in getting our own house in order and in bringing other nations to the table.

President Obama recognises the urgency. That is why he has made clear that the U.S. is prepared to play a leading role, both in getting our own house in order and in bringing other nations to the table. We have to work with other players such as the EU, China, India, and Brazil.

Together, we are making important progress. We can and must do more. For example, the U.S. and EU are pioneers of clean energy technology, and we are working together to deploy that technology to the developing countries where the need is greatest. Think about what cheap, abundant and clean energy sources could mean for less-developed nations striving to grow stronger and wealthier. We are also working alongside the UK, the Netherlands and others to limit investments in high-carbon energy infrastructure.

For the world to overcome the enormous threat climate change poses, we need every country to do everything within its power to pursue cleaner and healthier energy sources. We need to pursue the UN climate negotiations with vigour and determination toward an ambitious global agreement in Paris next year.

Even as we work together, every nation must also act on its own to develop and implement ambitious plans to reduce emissions and build a cleaner, more efficient and sustainable future.

When it comes to climate change, we cannot close our eyes and cover our ears. We cannot ignore the facts accepted by 97 per cent of the world’s climate change scientists. We cannot pretend not to know any better, and pursue policies that increase the threat instead of eliminating it when we have the means to meet this challenge in our hands.

The choices the world makes now will influence the lives of many generations to come. If we make the right choices, we can meet the challenge of climate change and create jobs and economic growth in every corner of the globe.

The U.S. is setting a responsible example. We will need leaders and people around the world to do the same.