Climate Change and Extreme Heat

This summer, parts of the USA, Europe, China, and South America have sweltered through extreme heat, sometimes referred to as “heat wave” conditions, although there’s no universal agreement on exactly what a heat wave is and no agreed-upon measure of the severity of extreme heat.

With such imprecision and ambiguity, naturally there is considerable confusion about the impact climate change (a.k.a. global warming) has on extreme heat. Too many people adopt the naive premise that the only effect of climate change is to make each heat wave a couple degrees hotter. The truth of the matter is that because extreme heat is extreme, it is by definition rare, and that is exactly the case in which a small change in the mean value — the result of global warming — can bring about a large change in the number and extremity of extremes. Everyone understands that rare events (like heat waves) are made hotter (on average), but few appreciate how profoundly they are made more common.

This is sometimes illustrated by a graph like this one, of the “probability density” of temperature

Arizona Republicans: Natural Gaslighting

Politico reports that Justine Wadsack — an extremely conservative Republican in the Arizona state senate — recently tweeted about the hot weather they’ve been suffering through, saying “This weather is normal.”

Meanwhile, Justin Heap — an extrememlly conservative Republican in the Arizona state house of reprsentatives — said “I don’t recall feeling that this July was particularly hotter than any other July that I remember.”

Natural gaslighting.

A High Schooler’s Take on the Climate Crisis

From The Deseret News in Utah:

Opinion:
By Cash Mendenhall

On July 17, Salt Lake City met the record for the highest summer temperature in recorded history, and by the time you read this that record may very well be broken.

We’re heading into the depth of a scorching summer with a worrying lack of clarity: Today, 99% of Utah is under either extreme or severe drought levels, with eight of the last 10 years being classified as drought years. We’ve become so desensitized to statistics like these in Utah and the West that heat waves and droughts barely register as policy issues, slipping under the radar of a rapidly metastasizing climate disaster. Eastern Utah has reported a temperature change over the last century triple that of the global temperature increase.

As a high school student, my generation is facing a steep collapse in livability.

French Heat

It’s hot these days, it’s unusually hot, even dangerously hot, in a lot of places a lot of the time. While America has been hit hard this summer, it seems that Europe has been hit even harder. Naturally, this causes a lot of people to speculate, or to outright declare, or to outright deny, that the frequency and severity of heat waves has been increased by man-made climate change, also known as “global warming.”

I decided to study a single location in Europe, the daily high temperature in a small region near the town of Beaune, France, known for centuries as an outstanding wine-making region.

I retrieved data from the ERA5 reanalysis, and for each year I isolated the data for summer, which is defined as the months of June, July, and August. Then I computed each year’s summer average temperature, giving this:

Not Even Wrong?

Cliff Mass shows a graph, taken from the Seattle Times, of the hottest temperature each July from 1945 through 2022 at Seattle/Tacoma airport (SEATAC). He then says “… and there is very little upward trend! How could this be?”

Then he goes further:

Just to check on the Seattle Times… I did the same thing for July and August over the past 50 years, plotting the warmest observed temperature at both SeaTac and Pasco (see below).

Hardly any change in the extreme high temperatures each year at either site. No long-term trend….and you would expect a trend if global warming was important for the extreme heat waves!

Unfortunately for Cliff Mass, the data contradict him.

Extra-Ordinary Heat Wave

The heatwave which invaded England recently was no ordinary one.

At numerous locations the temperature exceeded 40°C (104°F) which, as far as we know, has never before happened in the British Isles. England definitely isn’t prepared for such temperatures, as Melissa Harrison makes abundantly clear in the Washington Post; an airport closed when the runway deformed in the heat, railway tracks buckled, the London fire department got so many calls it was their busiest day since world war II. The U.K. Meteorological Office advised people (especially the young, the old, and the ill) to go nowhere and do nothing but stay hydrated.

Not an ordinary heat wave.

Correlation between CO2 climate forcing and Temperature

Since the subject came up …

There are certain claims (some false) about the correlation (or not) between CO₂ in the atmosphere and global temperature. Several folks have pointed out that we shouldn’t really be looking at the correlation between temperature and CO₂, but between temperature and CO₂ forcing.

Correlation between CO2 and Temperature

Here’s the global average temperature anomaly since 1880 (let’s use the data from NASA, shall we?).

Sea Level Rise: 30-year forecasts from NOAA

NOAA (National Oceanic and Atmospheric Administration) has caused quite a stir with their latest report about sea level rise. The statement attracting the most attention is:

Sea level along the U.S. coastline is projected to rise, on average, 10 – 12 inches (0.25 – 0.30 meters) in the next 30 years (2020 – 2050), which will be as much as the rise measured over the last 100 years (1920 – 2020).

The one getting far less attention than it should, is:

Sea level rise will vary regionally along U.S. coasts because of changes in both land and ocean height.

Unlike most of the critics of the report (especially the loudest ones), I actually took the time to read it.

Sea Level Denial

Back in 2010, the North Carolina’s Coastal Resource Commission published the North Carolina Sea Level Rise Assessment Report. Dave Burton of “NC-20” (a trade group for business interests in the coastal counties of NC) ridiculed their results, claiming that the only sensible way to forecast future sea level rise was to fit a straight line to the data from the past, and extrapolate that into the future.

Back in 2016, Florida’s Climate Science Advisory Panel (CSAP) produced a Recommended Projection of Sea Level Rise in the Tampa Bay Region. Willis Eschenbach ridiculed their results that sea level might rise faster than it has in the historical record, saying

“Finally, look at the St. Petersburg sea level dataset, or any Florida sea level dataset. None of them show any significant acceleration, despite covering the period of recent warming. Warming but no acceleration of sea level rise … oops.”

NOAA (National Oceanic and Atmospheric Administration), in their latest report, tell us that much of the U.S. may experience a foot of sea level rise by the year 2050. Anthony Watts ridicules their results, claiming instead that sea level has been rising at a steady rate for over a century and we have no reason to believe it will do otherwise.