We are the first generation to feel the sting of climate change, and we are the last generation that can do something about it.

The Democratic Party must nominate a candidate who will put fighting climate change at the top of the agenda. And that’s why I’m seriously considering running for president.

The science is clear. We have a short period of time to act. And whether we shrink from this challenge, or rise to it, is the biggest question we face, as a nation and as a people.

It is also our chance to realize the greatest economic opportunity of this century: to create millions of good-paying jobs building a future run on clean energy.

For millions of Americans, climate change is no longer just a chart or a graph. It’s the smoke on our tongues from massive wildfires. It’s the floodwater invading our homes, and record-breaking hurricanes and heat waves.

Confronting this change has been the driving force of my time in public life. About a decade ago, I co-wrote a book about the need to transform our economy to one run on clean energy and the need for a national Apollo mission-style project to take on this herculean task.

As governor of Washington, I’ve seen firsthand what’s possible when you invest in clean energy — reducing carbon pollution and supporting family-wage jobs that are growing twice as fast as those in any other industry.

In my state, I created a Clean Energy Fund and invested in electrifying our transportation system — from vehicles and buses to transit and even ferries. We need much, much larger investments that will be sustained over time, but we have the blueprint.

I was also the first governor to use executive authority to cap carbon pollution from all its largest sources. And this year we are pursuing a comprehensive suite of policies to achieve 100 percent clean electricity, increase energy efficiency in old buildings and promote net-zero energy in new buildings, require clean fuels and zero-emission vehicles, and eliminate climate super-pollutants.

Other states have been tremendous leaders in advancing climate solutions. The all-out national effort that we need can take some of its inspiration from strategies that have been pursued in our states.

But to win a national mandate for action everywhere, we must nominate a candidate who will deploy clean energy and cut carbon pollution on the ambitious scale required, even if it means deferring other worthy goals.

This will be hard. The oil companies, the big polluters and the climate deniers are incredibly powerful. They will do everything they can to protect their profits.

But our next president must summon the full energies of our nation to realize what the science is demanding of us. We must strive to achieve net-zero carbon pollution by midcentury, create a 100 percent clean-energy grid, and deploy new strategies and massive investments to transition off fossil fuels and decarbonize transportation, buildings and industries.

The reason I believe we are going to succeed in this — the reason I’m optimistic — is that this is a matter of character as much as it is a matter of science.

This is an issue of the basic, fundamental character of the American people. And I know something about the American people. We are optimists, can-do people. We invent, we create, we build. We do not shy away from a challenge. This is our nature.

Confronting climate change will require a full-scale mobilization — a national mission that must be led from the White House. This is the challenge we face and the choice facing American voters in 2020.