Nations meeting later this week in New York to sign the new global climate deal should announce fast plans for ratification and new, scaled-up actions to match what is needed to keep global warming below 1.5 degrees Celsius.

The Paris Agreement, approved in December last year, will be opened for signature at the United Nations Headquarters in New York on Friday, April 22nd. Crucially, as part of the deal, nations agreed to pursue efforts to keep warming under 1.5 degrees Celsius so as to avoid the very worst impacts of climate change.

As the leader of the World Wildlife Fund (WWF)'s Global Climate and Energy Initiative, I believe while it's good to have a global climate deal, there is no time to waste. More is needed, urgently. The planet just experienced the warmest 11 months ever. Very rapid, scaled-up action is necessary if we are to have any chance of staying under 1.5 degrees, the danger point for so much of the natural world and vulnerable people everywhere.

Signing the Agreement this week is just the first step. At least 55 countries, covering 55% of global emissions, need to take national actions to ratify, approve or accept the deal before it can take effect.

In New York, some countries will announce a fast process to do exactly this. I hope others will join them, so that it can become a reality as quickly as possible.

If the below-1.5-degree goal is to be more than words on paper, leaders will need to come to New York with big new commitments for action before 2020 on renewable energy, getting out of fossil fuels, conserving forests and climate finance. I think most people saw this before Paris, and they definitely hope to see it again in New York.

I expect that leaders in New York will be setting the tone for what will happen in Bonn, Germany when delegations meet next month to pick up where the Paris climate meeting left off. I hope that leaders will not only send strong signals to their negotiators, but even instruct them, about the key elements needed to give life to the Paris Agreement.

An important element of the Paris Agreement relates to forests and land use, which accounts for about a quarter of global carbon emissions, the largest source after the energy sector.

It was encouraging to see the key roles forests and land play in tackling climate change recognized through its inclusion in the Paris Agreement. Forests and land will make key contributions to closing the gigatonne emissions gap and to guaranteeing the stability of the climate regime in the long term.

According to the WWF, nations must now commit to the following in order to provide the momentum needed to realize the Paris Agreement:

● Implement more emission reduction actions in the immediate future (before 2020);

● Prove that five year review cycles can work by committing to increase ambition before or at the dialogue scheduled for 2018;

● Address the uncertainty that the Paris Agreement leaves about how climate action will be implemented equitably and fairly and;

● Deliver much more certainty on climate finance so that there will be sufficient resources for the transition to a zero-carbon economy, as well as to the already unavoidable impacts of climate change.