Climate change affects everybody. It doesn't care if you're black or white, rich or poor, male or female. Climate change affects everybody, and the notion that we can ignore it is just foolhardy. We are talking about the fate of our planet.

We're seeing global temperatures rise at an alarming rate. We're seeing the world's oceans warming at an alarming rate. We're seeing a growing number of climate refugees — even though that term isn't yet broadly recognized in international law — whether they are on the South Pacific island of Kiribati, on the North slopes of Alaska or in the Sahara. We have farmers dealing with changing soil and growing conditions. We have folks who are running out of clean running water because of drought.

There's not one part of the globe that's not being affected by this. Both on a national level and on a global level, there's nothing more pressing.

The average person understands this; the average person knows that there's something going on. And, the average American is looking for more leadership from elected officials on the federal level. In frustration, they're turning to their state and local officials, and saying, We want action. And so states and local governments are picking up the slack and enacting local and statewide ordinances to combat climate change.

I am optimistic — carefully optimistic — that we can make changes. Part of that is because I have found people to be receptive, when they have an open mind and don't come to these issues from an ideological viewpoint, that it can't be happening. Whether you're a conservative or a Democrat, a Republican or a liberal, people who are open to science and open to facts, they all agree that something's happening and that we need to address it.

Beyond that, I think you can look back 30 years ago, when the big environmental concern was the hole in the ozone layer. Scientists discovered in the mid-1970s that the chlorofluorocarbons we used in spray bottles destroyed atmospheric ozone (earning a Nobel prize), but it wasn't until 1985 that scientists proved that there was a huge and growing hole in the ozone layer above Antarctica. And guess what? On a global scale, we reduced the emissions of the CFCs through the negotiation of a treaty, the Montreal Protocol, in 1987. And we reversed the damage we'd caused; the hole is expected to completely heal by 2050.

With climate change, we've taken some steps. You can look at the Paris Accords from 2016; that was a great start. And no matter where we are from a federal standpoint — currently, we've withdrawn from the agreement — there are a number of states and local governments who have said that they're going to abide by the agreements and going to make a difference. And there are manufacturers that are saying that they want to abide by the accords, too.

So, I think there is hope.

From my perspective, on "Today," we've been trying to explain how climate change relates to your weather for the last 10 years. We are seeing these violent swings in weather and, while you can't point to one event and say that one was caused by climate change, the mechanisms that allow these violent weather events — rapidly intensifying hurricanes, major droughts, changes in the jet stream that are creating the never-ending fire seasons out West — make you sit up and take notice. We're not trying to preach to viewers, but just explain to them why this is happening. We can give people information as a tool, to allow them to be able to react intelligently and rationally.

But people can and will look at this information about the enormity of climate change and its effects and be overwhelmed. And so, as we go forward as journalists, our job also is to point out the things we can do as individuals to have an effect, even if it's a small thing, like maybe eating a little less meat.

I'm personally an avowed carnivore, but even I'm looking at how to reduce that carbon footprint of what I eat. I try to cut back on single use plastics: At work, I have a water bottle, a metal straw, and keep metal utensils around so I'm not using plastic. Or, when that's not possible, I'm using bamboo wood products, which are more environmentally friendly. Like everyone, I'm trying to find those little things that I can do as an individual, to help the sustainability of the planet as a whole.

This is the defining issue of our time. We need to start acting like it, in ways both big and small.

"Today" host Al Roker was recently named the head of NBC News’ climate unit, which is dedicated to covering the most important issues affecting the environment globally. The unit’s work kicked off Sept. 15 with a week-long series, “Climate in Crisis,” focused on climate issues.

As told to THINK editor Megan Carpentier, edited and condensed for clarity.