Climate-warming compounds that will be released by the charred forests long after the fires are extinguished may do more to warm up the planet than the immediate harm from smoky air.

Scientists say that only about 15 percent of a forest’s store of carbon is expelled during burns. The remainder is released slowly over the coming years and decades, as trees decay.That second hit of carbon, experts say, contains compounds that do more to accelerate climate change than those from the original fire. And future fires over previously burned ground could make climate prospects even more bleak.

“The worst possible situation is the fire that comes through and kills everything,”