About 50 million years ago, when mammals had just started taking over the planet, atmospheric CO2 levels were about 1000 ppm. And wow, was it hot here:
[A]round 50 million years ago there were crocodiles, palm trees, and sand tiger sharks in the Arctic Circle. On the other side of the blue-green orb, in waters that today would surround Antarctica, sea-surface temperatures might have topped an unthinkable 86degrees Fahrenheit, with near-tropical forests on Antarctica itself. There were perhaps even sprawling, febrile dead zones spanning the tropics, too hot even for animal or plant life of any sort.
[U]nder this past regime of high CO2, in the ancient U.K., Germany, and New Zealand, life endured mean annual temperatures of 23–29°C or 10–15°C warmer than modern times.
And yet, there is a seeming disconnect, between traditional projections for future warming—like those made by the International Panel on Climate Change (IPCC), which predicts around 4°C of warming by the end of the century under a business-as-usual emissions scenario (still frightening) and sea-level rise measured in mere inches (still frightening)—and the scarcely recognizable Earths buried in the rocks and created under similar CO2 regimes, like those that Eberle unearths.
One obvious way to reconcile this disparity is by noticing that the changes to the ancient earth took place over hundreds-of-thousands to millions of years and (IPCC graphs notwithstanding) that time won’t stop at the end of the 21st century. The changes that we’ve already set in motion, unless we act rapidly to countervail them, will similarly take millennia to fully unfold. The last time CO2 was at 400 ppm (as it is today) was 3 million years ago during the Pliocene epoch, when sea levels were perhaps 24 m higher than today. Clearly the climate is not yet at equilibrium for a 400-ppm world.
Good thing we've stopped pumping CO2 into the atmosphere! Oh, wait...
It's the hottest weekend of the year so far. We beat the high temperature on June 30th by half a degree (35.6°C v 36.1°C) yesterday, and so far today we've hovered around 32°C for the past four hours. So, naturally, I walked about 5 km earlier today to check out some open houses.
I'm ready for fall. Just as soon as I take my second shower of the day...
Temperatures in southern Portugal and Spain have reached 45°C as dust from the Sahara turns skies orange:
In the latest phase of a summer of extreme weather that has brought blistering heat to Britain, drought to the Netherlands and deadly wildfires to Greece, the heatwave affecting parts of southern Europe has reached a new intensity this weekend. According to IPMA, the Portuguese weather agency, about a third of the country’s meteorological stations broke temperature records on Saturday. The highest was 46.4°C in Alvega, 120km from Lisbon.
In the southern Algarve, more than 700 firefighters battled a forest fire that had spread across 1,000 hectares near the town of Monchique; in the capital, Lisbon, the usually busy terrace cafes of the Chiado district were quiet as people stayed indoors. And in Amareleja, a sleepy town as famous for its hot summers as for its full-bodied red wines, the large outdoor thermometer at the Farmácia Portugal read 44.5°C just after midday. Petrol station attendant Joaquim, however, was not fazed: the past couple of days had been abnormal, he said, but locals were “used to the heat and know how to adapt”.
The high temperatures in Portugal and Spain are caused by a plume of warm air from the Sahara, which yesterday turned the sky an eerie orange in places, including above Amareleja.
Meanwhile, the best President we have right now is trying to tank fuel-economy standards for cars.
Sediment under Lake Chichancanab on the Yucatan Peninsula has offered scientists a clearer view of what happened to the Mayan civilization:
Scientists have several theories about why the collapse happened, including deforestation, overpopulation and extreme drought. New research, published in Science Thursday, focuses on the drought and suggests, for the first time, how extreme it was.
[S]cientists found a 50 percent decrease in annual precipitation over more than 100 years, from 800 to 1,000 A.D. At times, the study shows, the decrease was as much as 70 percent.
The drought was previously known, but this study is the first to quantify the rainfall, relative humidity and evaporation at that time. It's also the first to combine multiple elemental analyses and modeling to determine the climate record during the Mayan civilization demise.
Many theories about the drought triggers exist, but there is no smoking gun some 1,000 years later. The drought coincides with the beginning of the Medieval Warm Period, thought to have been caused by a decrease in volcanic ash in the atmosphere and an increase in solar activity. Previous studies have shown that the Mayans’ deforestation may have also contributed. Deforestation tends to decrease the amount of moisture and destabilize the soil. Additional theories for the cause of the drought include changes to the atmospheric circulation and decline in tropical cyclone frequency, Evans said.
What this research has to do with the early 21st Century I'll leave as an exercise for the reader.
When I get home tonight, I'll need to read these (and so should you):
And now, I'm off to the Art Institute.
It's 25°C and partly cloudy today, so I'm spending as much as possible outside. Regular posting will resume when I'm once again trapped inside by some unfortunate event, like work.
As London broils in 34°C heat today, New Republic's Emily Atkin asks, "Why are some major news outlets still covering extreme weather like it's an act of God?"
The science is clear: Heat-trapping greenhouse gases have artificially increased the average temperature across the globe, making extreme heat events more likely. This has also increased the risk of frequent and more devastating wildfires, as prolonged heat dries soil and turns vegetation into tinder.
And yet, despite these facts, there’s no climate connection to be found in much news coverage of extreme weather events across the globe—even in historically climate-conscious outlets like NPR and The New York Times. These omissions, critics say, can affect how Americans view global warming and its impact on their lives.
Meanwhile, the Guardian (who, one hopes, have air conditioning in their offices) are reporting that 87% of the earth's oceans have human-caused damage.
London has very few air conditioners compared with North American cities, because the 30°C temperatures they've got right now happen so rarely it hasn't made a lot of sense to install them. But this heat wave is different:
The average July high in Stockholm, for example, is usually 23°C; this week, temperatures will crest 32°C, and there are 21 wildfires currently blazing across Sweden during its worst drought in 74 years. Some municipalities have resorted to sending leaflets to older residents to give them tips on how to manage the heat. Hospitals are shipping in otherwise rarely needed air conditioning units. Swimmers might be tempting to cool off in the city’s many waterways, but hot weather has caused giant algae blooms to appear within the Stockholm Archipelago, making the water unhealthy to swim in.
In the UK, severe dry conditions have also fed wildfires. Earlier this month, a large section of the grassy meadows at Wanstead Flats, on London’s eastern edge, burnt to ash—only to reignite again during another fire yesterday. This summer parts of the London region have received only six percent of their normal rainfall, leaving parks brown and reservoirs dry.
Parts of the UK may hit 36°C later this week, with torrential downpours predicted for Friday—a recipe for flash floods and massive property damage:
Several places have now had 54 consecutive dry days – meaning less than 1mm of rain – stretching back to 30 May, the longest spell since 1969 when 70 days passed with no significant rainfall, according to the Met Office.
The longest run of days with no rain at all this summer is 48 at Brooms Barn, near Bury St Edmunds.
A Met Office spokesman said: “For the UK as a whole we’ve only seen about 20% of the rainfall we’d normally expect throughout the whole summer. Parts of southern England have seen only 6%.”
Several longtime Daily Parker readers live in or are this week visiting the UK. Guys: how bad is it where you are? I'll be in the Big Stink on August 31st to find out for myself. I hope it's not as grim by then.
I've finally gotten around to extending the historical weather feature in Weather Now. Now, you can get any archival report that the system has, back to 2013. (I have many more archival reports from before then but they're not online.)
For example, here's the last time I arrived in London, or the time I took an amazing photo in Hermosa Beach, Calif.
I don't know why it took me so long to code this feature. It only took about 4 hours, including testing. And it also led me to fix a bug that has been in the feature since 2008.
A predicted consequence of anthropogenic climate change is that the air won't cool as quickly overnight, leading to ever-increasing temperatures overall. It's happening, and it's dangerous:
Nationwide, summer nights have warmed at nearly twice the rate of days, with overnight low temperatures increasing 0.8°C per century since 1895, when national temperature records began, compared to a daytime high increase of 0.4°C per century. (Nights have warmed faster than days during other seasons, too.)
While warm summer nights may seem less concerning than scorching afternoons, “the combination of high daytime and high nighttime temperatures can be really lethal because the body doesn’t have a chance to cool down during the nighttime hours,” said Lara Cushing, professor of environmental epidemiology at San Francisco State University.
Those risks are higher in places where temperatures have historically been cooler, like coastal California. There people are less physiologically acclimated (the body can get used to higher temperatures up to a point) and less behaviorally adapted to hot weather.
“A hundred and five degrees in San Francisco is going to have a bigger impact probably than 105 degrees in Houston, Tex., where everybody has air conditioning and people are accustomed to dealing with high temperatures,” Dr. Cushing said.
Older people, the sick, and young children are especially at risk. So are agricultural, construction and other outdoor workers, who can no longer avoid the heat by shifting their hours to work earlier or later in the day. Similarly, homeless people who bear the full brunt of the elements get little relief.
Never mind the rest of the local environment. Slower overnight cooling puts stress on plants as well.