Associated Press

The amount of land burned from wildfires has decreased nearly 25% across the planet in the past two decades, according to a new study. The reason? Humans have increased the acreage on Earth dedicated to growing food, which has substantially reduced the amount of forests and natural spaces that routinely experience fires.

Why it matters: Fires are a natural part of Earth's ecosystem — they clear dead trees from forests and keep plant growth in check in grasslands. The fact that there has been such a precipitous decline in natural fires globally has important ramifications for global warming, conservation and biodiversity.

What they found: The researchers took a global snapshot of fires based on satellite surveillance data collected between 1998 and 2015. The largest decrease in fires was found in savannas that have been converted to agricultural uses. "(The) long-term declines were more associated with transitions from natural to managed landscapes," the researchers wrote in Science. In these areas where humans had moved in, fire management techniques were "employed to protect high value crops, livestock, homes, infrastructure, and air quality."

Go deeper

How "naked ballots" could upend mail-in voting in Pennsylvania

Trump signs in Olyphant, Penn. Photo: Eric Baradat/AFP via Getty Images

Pennsylvania's Supreme Court ordered state officials last week to throw out mail-in ballots submitted without a required inner "secrecy" envelope in November's election, the Philadelphia Inquirer reports.

The state of play: The decision went under the radar alongside the simultaneous decision to extend the time that mail-in ballots could be counted, but Philadelphia's top elections official warned state legislators this week that throwing out so-called "naked ballots" could bring "electoral chaos" to the state and cause "tens of thousands of votes" to be thrown out — potentially tipping the presidential election.

Commission releases topics for first presidential debate

Moderator Chris Wallace. Photo: Drew Angerer/Getty Images

Fox News anchor Chris Wallace has selected what topics he'll cover while moderating the first presidential debate between President Trump and former Vice President Joe Biden next week.

What to watch: Topics for the Sept. 29 debate will include Trump and Biden's records, the Supreme Court, COVID-19, economic policy, racism and the integrity of the election, the Commission for Presidential Debates announced on Tuesday. Each topic will receive 15 minutes of conversation and will be presented in no particular order.

Fed chair warns economy will feel the weight of expired stimulus

Treasury Secretary Steven Mnuchin and Fed Chair Jay Powell bump elbows before House hearing on Tuesday. Photo: Joshua Roberts/Pool/AFP via Getty Images

Federal Reserve Chairman Jerome Powell told the House Financial Services Committee on Tuesday that the expiration of Congress' coronavirus stimulus will weigh on the U.S. economy.

Why it matters: Powell warned that the effects of dried-up benefits are a looming risk to the economy, even if the consequences aren't yet visible.

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