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For half a century, scientists have been warning about the risk of the planet warming by “2 degrees.” It’s a catchphrase that plagues the conversation about climate concerns, including at the United Nation’s COP30 meeting in Belém, Brazil, this month. Take U.N. General Assembly President Annalena Baerbock’s remarks to the press this week, in which she stated that member countries had previously committed to limiting global warming “well below two degrees.” That’s a huge mistake. Well, the math is right. But the wording, at least where Americans are concerned, is dead wrong.
“Two degrees” is a benchmark in Celsius. And the world’s leader in per capita carbon emissions—a leading culprit of the greenhouse gas effect warming the planet—is the United States. Americans speak in Fahrenheit. Many folks are already loath to take action to combat climate change. Thanks to the rallying cry of “2 degrees,” people in the U.S. are likely to mistake the dangerous warming of the planet as happening almost half as slowly.
Among U.N. member states, the U.S. is an outlier in sticking with the Fahrenheit scale. A few other smaller nations such as the Cayman Islands and Liberia, use it, too. But almost every other country in the world uses the Celsius system. Normally, I wouldn’t suggest kowtowing to the Americans and their strange instance on measuring things their own way. But if a bit of temperature translation will help light a fire, so to speak, in the perpetrators, it’s worth it.
In some ways, the 2-degree communication debacle is a home-grown problem for the United States. It was 50 years ago, within its borders, that Yale University economics professor William Nordhaus started the conversation around this benchmark by publishing papers warning that a rise in global temperatures of 2 or 3 degrees Celsius “would take the climate outside of the range” that humans had been living in for millennia. The focus around 2 degrees gained traction and became a central “speed limit” for climate change. Back in 2015, a report from the Carbon Brief noted that, “Limiting warming to no more than two degrees has become the de facto target for global climate policy.” That same year, a global treaty known as the Paris Agreement (which the U.S. had signed on to and, under Trump, has withdrawn from) set a target to keep global warming under a limit of 2 degrees. Nordhaus likely spoke in Celsius because it remains the temperature scale for researchers, regardless of where they are on Earth. This is similar to the way professional bakers, even in the States, measure in grams. People are willing to do those conversions to make sure their pastry doesn’t burn. They don’t seem willing to do the same for their planet.
A difference of 2 degrees Celsius is, depending on the exact temperature on the scale, equivalent to around 3.6 degrees Fahrenheit. That might sound like splitting hairs, but consider this: Climate warming is not linear. Each degree increase accelerates the problem. Take the example of measuring a child’s temperature. Let’s say it starts out at 39 degrees Celsius. That’s equal to 102.2 degrees Fahrenheit—a true fever. But a “2-degree” Celsius increase isn’t equivalent to reaching 104.2 Fahrenheit (still a fever, but manageable at home). Forty-one degrees Celsius equals 105.8 degrees Fahrenheit—a medical emergency that would mean an immediate trip to the ER, at the very least, or a call for an ambulance.
Americans may not understand that scientists talking about a 2-degree difference in climate are speaking about what translates into more—often around double the rise in number—in Fahrenheit. And yet, even some prominent television and news coverage centers around the issue of 2 degrees, sometimes without even giving the Fahrenheit conversion. Even NASA, a U.S. agency, has published a headline in Celsius (an easy mistake for a science-focused institution to make). The Wikipedia page on the “2 degree climate target” doesn’t, as of this writing, include a mention of a Fahrenheit equivalent.
Between 1970 and 2023, the global average temperature already increased about 1.7 degrees Fahrenheit. We’re warned that at 3.6 degrees Fahrenheit warmer—the equivalent of the famous 2-degree Celsius benchmark—somewhere between 800 million to 3 billion people would face chronic water scarcity. And, unfortunately, the United Nations Environment Programme has stated that at the rate we’re going, we’re on track for a 5-degree Fahrenheit rise in average global temperatures by the end of the century. Perhaps no issue is more important than global warming when it comes to the future of the world and the lives our children will lead. If a conversion can help even a few more Americans understand it, it’s worth a shot.
I’m not suggesting that the temperature conversion could solve the problem of climate apathy. But a few small changes could help: Headlines in U.S. outlets should be in Fahrenheit. U.N. leaders need to go to greater lengths to translate their message into Fahrenheit, in addition to Celsius. To put it another way, they don’t need to go the extra kilometer to make sure we all know how dire things could become—they need to go the extra mile.
