Part of Bernie Sanders' endorsement of presumptive Democratic nominee Joe Biden is a new plan for them to form joint "task forces" on six big topics, including climate change.

Why it matters: Time will tell, but I'll be watching to see if it leads to substantial changes in Biden's climate platform, which has disappointed the left even though it goes far beyond Obama-era policies.

Biden already rolled out changes to his health care and student debt policies last week designed to appeal to Sanders' backers.

Driving the news: The two men said they would form task forces on climate, health care, criminal justice, immigration, the economy and education.

Axios' Alexi McCammond writes that it's a sign of Biden's continued outreach to the progressive wing of the party.

What we don't know: Who will be on the climate task force, but I'll write more when I know something.

“They will be comprised of policy experts and leaders that represent the diverse viewpoints of the Democratic party,” a Biden campaign aide tells me.

“The groups will work together to identify shared policy goals that build upon Vice President Biden’s progressive vision for America,” the aide said.

Go deeper: The energy stakes of Bernie vs. Biden