(CNN)Since Russia closed its airspace to airlines from dozens of countries at the end of February -- in response to sanctions levied for its invasion of Ukraine -- about 400 flights per month that had previously been routed over the country are being forced to take a wider berth, according to Flightradar24.
Flights are taking huge 'detours' around Russian air space. Here's what that means for the climate crisis
In lieu of using Russian airspace, some flights from Europe to Asia are flying south of the country or, in some cases, taking a painfully long reroute over the Arctic. And Russia is huge; it's the largest country on the planet -- larger than the continent of Antarctica.
The new routes are leading to more time in the air for passengers and crew, more miles flown and more fuel burned -- which means more planet-warming emissions.
Japan Airlines Flight JL43 from Tokyo to London, for instance, uses a Boeing 777-300ER aircraft that burns roughly 2,300 gallons of fuel per hour. The rerouted JL43 flight -- which now heads east over the North Pacific, Alaska, Canada and Greenland -- added 2.4 hours of flight time and likely burned around 5,600 gallons more fuel, a 20% increase.
That means Flight JL43 could be emitting an additional 54,000 kilograms, or 60 tons, of planet-warming carbon dioxide into the atmosphere, according to calculations by Paul Williams, an atmospheric scientist at the University of Reading, for CNN. That's the same amount of carbon dioxide as the average car driving 137,000 miles, or nearly six times around the planet.
Williams said the exact fuel burn rate depends on the weight of the aircraft, the altitude and airspeed, and some of those variables are unknown. These calculations also do not factor in the warming effect of other greenhouse gas emissions or the flights' condensation trails.
"Naturally, a lot of people when thinking about aviation and climate, they focus on the CO2 emitted," Williams told CNN. "But, actually, it's much worse than that. CO2 is actually just the tip of the iceberg. The extra flight time is causing a lot more warming than the mileages I gave you because they only take into account the CO2, not the other non-CO2 effects."
Dan Rutherford, director of the International Council on Clean Transportation's aviation and marine programs, told CNN that Williams' calculations "look reasonable."
"If anything, he is underestimating the likely impact because, at the margin, long-haul flights become even more fuel intensive with extra distance because they 'burn fuel to carry fuel,' in industry parlance," Rutherford said.
In other words, it's a vicious, fuel-guzzling loop: It takes more fuel to carry the weight of more fuel.
According to Flightradar24, the aircraft tracking service, there are a limited number of flights -- mostly Finnair flights -- taking the polar route around Russia. Others are taking a southern route.
Lufthansa Flight LH716 from Frankfurt to Tokyo, for example, has added nearly an hour to its flight time. The Airbus A340 aircraft typically burns around 2,000 gallons of fuel an hour, which could mean the extra flight time burned another 1,428 gallons of fuel.
That's an additional 13,710 kilograms of planet-warming emissions -- the same amount released by an average car driving 34,000 miles, or nearly twice around the world.
Rutherford estimated that if Russian airspace remains closed for much longer, the global aviation carbon inventory may increase by up to 1%.