If you listened to the news over the holiday, you might have learned that it was not just exceptionally warm across much of the United States, but Monday was the hottest day in history. Or at least, the hottest day around the globe since temperature records have been maintained.
It was the first day in recorded history that the world had ever averaged over 17 degrees Celsius. That’s just 62.62 degrees Fahrenheit. It might not seem like all that much, but keep in mind that for half the world, this is mid-winter. Also, the world includes Greenland, Antarctica, and some similarly chilly places. To reach a 17.01°C average means that a great deal of the planet was just exceptionally toasty.
The new record beats a previous peak of 16.92°C that had stood since August 2016. However, the new record didn’t stand nearly so long, because the average temperature on Tuesday was 17.18°C. That means Monday was the hottest day in history. Then Tuesday was the hottest day in history.
And we’re still weeks away from the usual hottest days of the year.
This is just part of a global climate now unraveling at a rate that matches the most frightening predictions, with both sea and land heating up at an unprecedented rate.
Saying that July 4, 2023, was the hottest day in history is actually wrong for a couple of reasons. First, we’ve been keeping records of the temperature in many parts of the world since the middle of the 18th century, but history goes back considerably longer. However, we have other means of measuring temperatures, from tree rings to ice cores to isotopes in the shells of ocean creatures.
That allows us to say with some confidence that July 4, 2023, wasn’t the hottest day in history: It was the hottest day in over 125,000 years. That’s long enough that the last time such a temperature may have occurred, there were no less than five different human species on the planet. The cave paintings at Lascaux were over 100,000 years in the future.
That chart above shows just how far from normal this year has been. 2022 also hovered at the top of the charts, but for the past several years a La Niña current has kept the eastern part of the Pacific, and the air that flows across it, cooler than might be expected. Now that the cycle has flipped to a warm El Niño current (we don’t know for how long), the ocean is giving up some of its stored heat—and it has a lot of heat to give. For the U.S., that means that record-high temperatures are likely to be around in many areas for weeks to come, but the implications for climate actually stretch around the globe.
This gives some sense of the tremendous amount of heat energy stored in the oceans, but doesn’t really drive home the impact. For years—decades, even—heat energy has been pumped into the deep oceans. Even as we’ve observed many aspects of climate change on land and at the sea surface, the real scope of changes has been hidden from us, down in places where humans rarely travel, affecting ecosystems we know little about.
That heat is now rising, and what we’re seeing is so amazing that scientists are having trouble grasping the abrupt change.
All of that is frightening. But none of these charts are the really scary chart. This is the really scary chart:
This one takes a little more explaining that the others. When you think about how much heat energy the Earth receives from the sun, how much of that energy is reflected, or radiated, back into space?
The answer is, or at least should be, 100%.
This seems counterintuitive, because clearly the Earth is warmed by the sun. But if the system doesn’t reach a level where it is 100%, then there’s a grim outcome: The Earth keeps getting hotter until it finally reaches a point, whatever that point may be, where it is passing on 100% of the sun’s heat. For example, see Venus. Venus radiates away 100% of the heat it receives. It has found equilibrium … at an average surface temperature of about 475°C (900° F).
Earth isn’t going to be Venus, at least not any time soon. But what the chart above shows is that over the past couple of decades the difference between what the Earth takes in from the sun, and what it gives away to space, has increased sharply. That difference—now at about 1.8 watt hours per square meter—may not seem like much; barely enough to light a dim LED. That is, until you consider that the Earth has around 510 trillion square meters of surface. What’s actually being gained is the equivalent energy of over 1 million Hiroshima bombs per day.
As climate crisis skeptics love to point out, there are long-term oscillations in this heat imbalance over both a 10-year and longer cycles. However, like those temperatures, the highs we’re seeing now are greater than past peaks. Also, when the chart was high in the past, the Earth responded—by warming. That’s the usual cycle. The Earth gets to the point where it’s not radiating out 100% of the heat, and it warms. Then it gets to a point where it’s radiating more than 100%, and it cools. Over the several thousand-year span of human history, it has basically evened out.
However, the last time the imbalance flirted with zero was in 1980. So the idea that past peaks in the imbalance somehow make this one okay is more than a little deceptive. What the imbalance says now is that the Earth isn’t just hotter, it’s going to get hotter until it pushes that imbalance back to a net zero. The imbalance will cycle back to zero, or lower. We just don’t know what the climate will look like when it does.
In the meantime, be on the lookout for another hottest day in history, and another one after that. They’re coming.
However, that doesn’t mean we’re doomed. Because we’re not. Take a look at New Mexico.
As late as 2008, I was out in New Mexico, working at an enormous surface mine for coal near the town of Grants. That mine supplied a power plant, also in New Mexico. There was another large coal-fired power plant in the Navajo Nation at Kayenta, Arizona. And yes, I worked at that mine, as well.
In the years since, the Arizona mine has closed. Production at the New Mexico mine has dropped by two-thirds. Kayenta is now home to the Navajo Nation Kayenta Solar Project, and New Mexico has gone from one of the most fossil fuel-dependent states to a template for change.
Just this year, New Mexico gained a permanent Office of Renewable Energy, and a requirement that developments on public land use renewable energy. It is not just on track, but ahead of schedule for delivering 100% of the state’s energy through renewable methods by 2045.
It took just eight days of the 2023 legislative session for the New Mexico Senate to pass the latest bill pushing the state into a renewable future on a 23-15 vote. By a non-coincidence, the New Mexico state Senate has 27 Democrats and 15 Republicans. Four Democrats were absent on the day of the party-line vote.
As we face the hottest day in history again and again, there are steps you can take in your personal life to help see that your state and America take the actions that are necessary to bring the Earth back into equilibrium as soon as possible. You can avoid unnecessary travel, take advantage of public transit when possible, and look for ways to cut your home energy budget.
But there may be just one action you can take that’s more important than any of the others: Vote for Democrats.