What will we say to our grandchildren, as we dither over the solution to arrest climate change that lays before our eyes?

If temperatures are allowed to rise past 1.5ºC, island countries like ours will be in grave danger, with some facing the grim prospect of being wiped off the map by rising seas. The climate impacts will affect millions of people around the world, in both developed and developing nations.

We also now know that it is already too late to keep warming to 1.5ºC by reducing global emissions alone. If we hope to meet the 1.5-degree target and save our countries from devastating impacts, we must find ways to actively remove from the air a large amount of carbon dioxide that has already been emitted.

Building a zero-carbon economy will be difficult, but we know what we must do. We must make a rapid shift from burning fossil fuels to powering economies with carbon-free energy. But how do we remove enough of the carbon dioxide that has already been emitted into the air and is already causing climate breakdown to keep the global temperature from rising above 1.5 degrees?

There are a number of ideas that involve human-engineered technology. These are still in the early stages of development, and we need to continue to explore their ultimate potential. But there is a way to remove carbon from the atmosphere right now. It is to use what are called “natural” or “nature-based” climate solutions.

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Natural climate solutions are cheap, effective and ready to deploy, because they use the power of nature rather than machines. They involve using nature to draw carbon from the atmosphere. There are numerous different approaches, but the greatest potential lies in sustainably managing marine habitats, protecting natural forests, restoring deforested and degraded lands and improving agricultural practices. All of these can create sustainable and vibrant landscapes and ecosystems while storing billions of tonnes of additional carbon.

These solutions also present some very clear and powerful opportunities for island nations like ours. We have mangroves and seagrass beds, which once were abundant. These ecosystems can be restored, extended and strengthened. Not only do they provide vital protection for our coastal infrastructure and communities, they also sequester carbon at a much greater rate than terrestrial forests.

Let us understand that we must aggressively pursue natural climate solutions in parallel with our efforts to reduce emissions. Natural climate solutions alone will not prevent climate catastrophe if they are used as an excuse to delay cutting emissions. This is not an either-or situation. Both are required, and urgently.

We are very pleased to see some fresh momentum from a broad group of climate leaders and other key figures around the world who have just issued a call to governments to support natural climate solutions with an urgent programme of research, funding and political commitment.

This couldn’t come at a more important time. Unfortunately, natural climate solutions are currently receiving just a tiny fraction of the overall funding aimed at reducing emissions. At this level, we are denying ourselves a solution that could deliver about a third of the greenhouse gas reductions we need by 2030.

Political leaders need to step up their support for natural climate solutions. We need to commit to exploring opportunities to maximise the contributions of forests, lands and oceans in our next round of national climate commitments. We need to develop effective methods for international cooperation. And we need to work closely with the private sector to mobilise much higher levels of financing. If we can do this, along with urgent action on other fronts, we will have a chance of keeping 1.5 degree within reach. There really is no alternative.

This is a rare opportunity to inject a dose of optimism into the climate debate. We hope people around the world will join us in calling on political leaders everywhere to commit to unleashing the power of nature. We spend a great deal of time and energy debating the problem. How often are we presented with the chance to come to consensus around a genuine solution?

And who among us would want to face our grandchildren and tell them that we knew what we needed to do, but we simply failed to grasp the solution that was before our eyes?

Frank Bainimarama is Prime Minister of Fiji, and Mohamed Nasheed is the former President of the Maldives