Democratic presidential candidate Joe Biden ranks near bottom of the field of 2020 hopefuls on environmental issues, according to the left-leaning environmental group Greenpeace USA.

In a newly released climate scorecard, Greenpeace USA gave Biden a "D-", the second-worst among Democrats. Washington Gov. Jay Inslee received the highest score, an "A-", followed by Vermont Sen. Bernie Sanders and New Jersey Sen. Cory Booker, who both were awarded "B+".

"Even though Biden introduced the first-ever climate bill in Congress back in 1987, he has yet to release a plan that tackles the climate crisis if elected in 2020," Greenpeace said. "Biden has not endorsed the Green New Deal, nor committed to phase out fossil fuels. He has also not taken the No Fossil Fuel Money Pledge. All candidates must pledge to make bold climate action a Day One priority in office."

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The group scored the field of candidates based on based on their commitment to ending the use of fossil fuels, as well as their voting records, proposals and public statements on climate issues. Some candidates also answered the organization's 29-question survey, which factored into their scores.

"If he wants to translate his frontrunner status in the polls to actual leadership on climate, we need him to come out with a bold, concrete plan in line with the scale of the crisis we're facing," Greenpeace USA Climate Campaign Director Janet Redman said in a statement.

In his stump speech, Biden often refers to climate change as an "existential threat." But earlier this month the former vice president came under fire from environmental groups after Reuters reported he would propose a "middle ground" approach that would include continued use of fossil fuels like natural gas.

The Biden campaign refuted that report, but the article caught the attention of Rep. Alexandria Ocasio-Cortez, who appeared to take a shot at Biden during a rally supporting the Green New Deal.

"I will be damned if the same politicians who refused to act then are going to try to come back today and say we need a middle-of-the-road approach to save our lives," she said.

Biden rejected Ocasio-Cortez's criticisms, telling reporters, "I've never been middle of the road on climate. And tell her to look at the statements I made and look at my record. She'll find that nobody has been more consistent about our environment and the green revolution than I have."