In recent weeks, wildfires—largely a result of increasingly frequent or more severe drought—devouring entire communities in California, have left thousands homeless and millions with air polluted by smoke. Meanwhile, scientists report that ever-more powerful heat waves have cost the lives of tens of thousands in recent years.

The climate crisis is fast becoming the greatest health crisis we’ve ever seen.

It is already taking a toll on our lives by worsening heat waves, increasing spread of infectious diseases, causing harmful air pollution and threatening our food security. It is not an exaggeration to say that the climate crisis poses serious and urgent threats to millions of people on the planet, especially the poor, the elderly, children and those already suffering from existing illnesses.

Extreme heat is already bringing some parts of the world to the brink of uninhabitability. Here in the United States, heat waves are sending more and more people to the emergency room and causing more deaths each year than hurricanes, tornadoes and floods combined.

At the same time, rising temperatures add even more energy and fury to the devastating storms we see leveling communities from the Carolinas to the Philippines during increasingly deadly hurricane and typhoon seasons.

A warmer world also means a friendlier world for mosquitos and other pests that carry infectious diseases like Zika, malaria and Lyme. Not only are these vectors able to live longer and reproduce more often, but they’re also able to travel and spread these diseases farther than before. Mosquitos already kill more people each year than all other species—including humans—combined, so increasing numbers and ranges due to warmer temperatures will only exacerbate their impact.

We can trace a direct line from burning fossil fuels to the higher temperatures making our world an increasingly dangerous place. But perhaps the most immediate and widespread health impact of pumping dangerous emissions into our atmosphere is the air pollution it brings to our cities and towns.

According to the 24 Hours of Reality: Protect Our Planet, Protect Ourselves.

Over the course of 24 hours of stories, interviews and conversations, we’ll travel around the globe to explore not only the climate crisis but also how communities everywhere are embracing clean energy and creating a healthier future.

The climate crisis is our greatest challenge. Join us for 24 Hours of Reality to learn how you can be part of the solution.