The World Meteorological Organization (WMO) has just confirmed that 2014 was the hottest year on record, and worryingly they say that this is part of a continuing trend. In fact, 14 of the 15 hottest years have all been this century. The trend is clear.

Global warming is expected to continue given the rising levels of greenhouse gases in the atmosphere and the increasing heat content of the oceans, committing us almost irrevocably to a warming future.

This is something we know. We have experienced it. Millions of people have their lives and livelihoods impacted by climate change through extreme weather, changing weather and irregular weather.

For 20 years we have been in global negotiations to do something about climate change, with little progress so far.

The good news is the world’s governments seem to have woken up to the realities of climate change. The time for doubts and denials is past. But now we’re facing a new challenge: the actions that are being proposed to tackle climate-changing emissions are mainly too unambitious – and too slow – to have the required impact.

There’s a big gap between what the world’s climate scientists are telling us needs to happen, in order to avoid catastrophic consequences, and what is actually being done.

And when we say a big gap, we mean gigantic. Greenhouse gas emissions (particularly carbon dioxide, but also methane and hydrofluorocarbons) aren’t just a little bit over what they ought to be. The world is still pumping several billion tonnes more greenhouse gases into the atmosphere than we should, even to stay within the “least damaging” target of a 2average temperature rise.

A billion tonnes is a gigatonne. That’s why we call this overshoot ‘the gigatonne gap’.

Even if a global climate agreement is reached in Paris this December, as we hope, most of the proposals and targets for cutting emissions won’t kick in until after 2020. But these five years, from 2015 to 2020, are absolutely vital in the battle against disastrous climate change.

This is the five years when global emissions should be peaking, or starting to plateau before falling. We can’t just allow emission figures to drift ever upwards – otherwise the long-term targets will become even harder to meet.

WWF is determined to help close the gigatonne gap – but we need the world’s governments to show leadership, foresight and determination, and start making urgent changes right now.

We can’t afford to waste these crucial, precious five years.

Samantha Smith

Leader, WWF’s Global Climate and Energy Initiative