Christiana Figueres is a Costa Rican diplomat who spearheaded the 2015 Paris climate accord. Greta Thunberg is a 16-year-old Swedish student leading a global school strike for climate.

DAVOS, Switzerland — Climate change is an existential threat to humanity and already a matter of life and death for many, but it is just one issue among many on the agenda at this year’s World Economic Forum. It should be the number one priority and should sit at the center of every conversation in Davos.

This week, the two of us — from different generations but united by the same concern for our planet — will jointly address delegates at the forum. Climate change action has never been so urgent, as we are quickly approaching tipping points of no return. In that context, we will talk about leadership, outrage and optimism. We believe these are inspirational times for transformational change.

In Paris in 2015, the world’s governments agreed to hold global warming to well below 2 degrees Celsius above pre-industrial levels, while striving to keep the rise to 1.5 degrees by the second half of this century. Then in October last year, the Intergovernmental Panel on Climate Change provided the most granular and authoritative scientific assessment yet on the impacts of climate change. It showed that the difference between allowing an increase in average global temperatures of 2 degrees instead of 1.5 degrees would mean twice as many life-threatening heat waves and the loss of nearly all the world’s coral reefs. Even a 1.5-degree increase means that children growing up today will inherit a depleted and suffering planet.

The Paris climate accord was a historical achievement. It was one of the only times in world history that all countries united behind a single agenda — to help save humanity from the existential threat of climate change. But we knew that the first set of national efforts was going to be insufficient to stabilize the atmosphere.

That is why countries signing the agreement pledged to step up their efforts to cut greenhouse gas emissions every five years. 2020 is the first test of those pledges. 2020 is also the year we must bend the curve of global emissions sharply down toward net zero by 2050 to give us the best chance of keeping warming to 1.5 degrees.

But worryingly, global greenhouse gas emissions continue to rise. In 2018, carbon dioxide emissions increased by more than 2 percent because countries keep on burning fossil fuels, and investors continue to fund them. At a time when our future is at stake, investments in cheap and reliable renewable energy have been slowing. New power plants are under construction today that will burn coal for decades, and energy companies are still searching for new oil and gas reserves.

Burning fossil fuels pollutes the air we breathe, contributing to the premature deaths of over 7 million people each year, according to the World Health Organization. Seven million people’s lives cut short every single year from dirty air. Seven million people missing their next birthday or school exam or grandchild’s graduation.

Air pollution kills more people than tobacco does. In places like Delhi, people who have never smoked a cigarette are dying of lung cancer. Polluted air kills three times as many people as AIDS, tuberculosis and malaria — combined.

But like climate change, air pollution is not a priority for many of the leaders gathered here in Davos. This is outrageous, especially because there are feasible solutions to the crisis that could save lives and create high-quality jobs.

Here’s a three-step “find and replace” exercise for leaders gathered in Davos to enact that will immediately clean up our air and help safeguard our climate:

  • Find coal, and replace it with renewable energy supported by storage.
  • Find internal combustion engines, and replace them with zero-emissions mobility.
  • Find crop burning (when farmers burn the stubble left over from the harvest to clear the ground quickly for new planting) and replace it with “no till” and “low till” technologies that enrich the soil instead of burning its nutrients.

Bold decisive action on coal, combustion engines and crop burning — across direct operations, investment portfolios and supply chains — requires real leadership. While these steps are being implemented in some places, it is not yet enough.

That’s why in nearly every continent, students have joined the school strike for climate, declaring that they want a different future, that they are unstoppable and that another world is possible. Tens of thousands of students in Switzerland, Belgium, Germany, Australia and elsewhere have joined the strike. Their leadership is powerful. Transformational change is coming.

The two of us are from different generations, yet we stand together in Davos, hoping to be joined by more people of all ages and from all places. We are going to do everything we can to put an end to dirty fuels and dirty air so we can improve the prospects of people everywhere. The future is going to be tremendous.

This was produced by The WorldPost, a partnership of the Berggruen Institute and The Washington Post.