The move would give him additional powers to push his renewable energy agenda, which has been held up by lack of support in Congress.
Mr Kerry told the BBC it was “less than ideal” that Congress was not “full-throatedly” in favour.
But he said nobody was more committed than President Biden to replacing carbon-based energy.
Mr Kerry also said recent Supreme Court rulings restricting the government’s environmental policies had not helped.
Climate change increases the risk of the hot, dry weather that is likely to fuel wildfires.
The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.
Tens of millions of people in the US, across more than two dozen states, have been living under heat warnings during the past week.
But Mr Biden’s efforts to pass a climate change bill were dealt a blow earlier this month when West Virginia Senator Joe Manchin – a conservative Democrat – said he would not vote for the legislation.
On Wednesday, Mr Biden announced $2.3bn (£1.9bn) to help build infrastructure that can withstand extreme weather and natural disasters.
However, he stopped short of formally declaring a climate emergency, despite mounting pressure to do so from fellow Democrats and environmental groups.
Mr Kerry said the world was learning that green energy reduced inflation, lowered energy costs, created jobs and improved health and security.
He said Mr Biden was prepared to use “every tool available to him” to tackle climate change, including executive orders.