CNN  — 

I’ve been a meteorologist at CNN since 1999. And for a long time I didn’t think that global warming gasses would overwhelm the earth enough to change its climate.

As a skeptic, I didn’t deny climate change existed. I was questioning the data behind the science. One big number ultimately changed my mind.

Watch this video to learn what it is:

00:51 - Source: CNN
I used to be a climate skeptic. This fact changed my mind

That was on April 23, 2013.

After that day I started attending climate conferences, and continued to consume more and more of the data coming in about climate change. I like to say that I didn’t go from denier to believer; I went from skeptic to scholar. And along the way I learned a lot about the climate crisis that I hope will help YOU better understand it as well.

For instance, I quickly learned the problem was way bigger than just carbon dioxide:

01:26 - Source: CNN
It's not only CO2. These greenhouse gasses are just as bad

Over the last millennium, the concentration of these gasses in the atmosphere has gone up and down. In tandem, global temperatures have also become warmer, colder and then warmer again. That’s why so many skeptics say climate change is cyclical, and point to that as evidence against global warming.

But what we’re experiencing now is much more extreme than in the past:

01:19 - Source: CNN
Climate change is cyclical, but this is worse

As this alarming rate of warming continues, it is evident that humans are responsible. And not always in the ways you might think:

01:15 - Source: CNN
Car exhaust isn't the only climate change contributor

All of these issues are contributing to global warming – a term that often gets misused, especially during an epic snowstorm or freezing spell during the winter months.

The problem is that people are only looking at the weather out their windows:

01:09 - Source: CNN
It's snowing. Where is global warming?

When you look at the crisis from a global perspective, you start to see evidence of a devastating future:

01:18 - Source: CNN
What we'll have to endure as the climate crisis gets worse

Maybe you see the climate crisis as I do now. Maybe you need some more time to gather your own evidence and look closely at the facts. Whenever you’re ready, the next step is to figure out how you can start making a difference:

01:13 - Source: CNN
What you can actually do to slow the climate crisis

Contributing video editors: Jeffrey Kopp, Lacey Russell
Motion graphics: Melody Shih