Greenpeace activists block the outflow pipe at AKZO in Delfzijl. 03/07/1990 © Greenpeace / Benno Neeleman

2015 has barely begun, but it has already been called "the most crucial year in decades for the climate battle" and a "watershed" year for sustainable development worldwide. Naomi Klein is convinced that 2015 is a once-in-a-generation moment for the climate battle and Avaaz has just told their supporters that we have ten months left to save the world.

What's going on?

World leaders will meet in September to agree upon new goals for all of humanity: the Sustainable Development Goals. And, in December in Paris, another attempt will be made to deliver a global climate agreement. Both summits will be huge, and will get a lot of media attention. Some of our allies have called them "opportunities of a lifetime" and many, including Pharrell Williams, are starting to organize events to mobilize public support for a greener future.

There is no question about the urgency to act. Scientists have just told us that, out of nine vital planetary support systems we need to survive, four have exceeded "safe" levels already. Signs of climate change are starting to appear all around us. Plummeting oil prices, meanwhile, are making risky investments, such as Arctic oil, look even more insane.

It's true that global rules for people and planet are needed now more than ever. However, there is no need to wait for any more summits. Summits can help, because they can act as deadlines. They can force governments to find time to pass legislation or get squabbling ministries to agree on a plan. They can provide additional public attention to an issue, which can be an essential agreement to break a political deadlock. We would probably never have achieved this month's step forward for the protection of the High Seas – almost half of our planet – if we hadn't used the Rio+20 Summit in 2012 to give this issue additional political prominence (and a deadline, which was narrowly met).

And summits can also be places where governments send long-term signals to markets. For example, the Paris climate summit in December could agree to bring global carbon pollution down to zero by 2050. That is, at the moment, one option governments are considering. If they adopt it we could see the end of the fossil fuel era. It would certainly make investors in fossil fuels lose some sleep.

We will work for that. And use the two summits this year as opportunities to call for a future without carbon. A future in which all people have electricity – and it's 100% renewable.

The real "opportunities of a lifetime", however, are actual changes catalyzed on the ground. This is what we all must strive for in 2015. And if we do, the good news is that those real changes on the ground increase the likelihood of better global agreements!

The energy revolution, for example, has started already all over the world. 2014 saw China use less coal for the first time this century and install as much solar capacity in one year as the US has ever done. These domestic changes have made it possible for China to pledge that they will stop their relentless rise in climate pollution by 2030 at the latest. That's not good enough – yet – for a safe future. But, if we manage to seriously shift away from coal in China this year – and end the airmagaddon in China's cities – it will not just end unlivable smog for millions of Chinese people. A continued decline in China's coal use would also make it more likely for China to make an even more ambitious pledge internationally...

To make 2015 matter, we need to attack the fossil fuel industry interests who are holding back better and faster climate action head on.

Therefore, this year, we will be fighting the carbon projects that simply must not go ahead if our children are to avoid climate chaos. That's why we will continue to stop oil drilling in the Arctic.

Join our call on President Obama to take a stand on the Arctic here.

And that's why we will be taking on coal and supporting renewables all over the world – from India and China to Germany and the United States. Right now, we are focusing on driving back Australia's coal expansion.

If you think financial institutions should not be risking the beautiful Great Barrier Reef for the short-term pursuit of coal join us here.

We must make 2015 a watershed year together. We can make this year count by building movements that force real change, from the Arctic to Australia. We have, as we have headlined in previous campaigns, "No Time to Waste".

But, whatever happens at the big summits this year, we will need all of you to continue pushing for faster and more fundamental changes in 2016. The world will not be saved once and for all in Paris in 10 months. But we can make real progress this year in stopping those who are destroying our planet. We need you to accelerate an energy revolution that delivers for all. We can use the summits as platforms to make that change.

But only if you join in!

Daniel Mittler is the Political Director of Greenpeace International.