Andrew Dessler
@AndrewDessler
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Prof of Atmospheric Sciences & climate scientist @ Texas A&M; AGU and AAAS Fellow; Native Texan; find out what I think at
College Station, TX
Joined August 2013
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profile picture pupdate: strong consensus for: dog, but more professional.
Introducing my new profile pic:
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One of the things you learn as a scientist is the ability to look at a plot and think, "that just doesn't look right." That's the feeling I got when I saw this plot that Lomborg is currently pushing.
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if you're wondering why climate impacts seem to be getting much worse suddenly, let me introduce you to the concept of non-linearity. A short 🧵:
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If you don't like all of the climate disasters happening in 2020, I have some bad news for you about the rest of your life.
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I just got a copy of the embargoed IPCC Summary for Policymakers. I hate to break the embargo, but this is too important to wait. Here it is, the entire SPM. Surprisingly, it's just one paragraph long.
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one of my favorite things about eclipses: if you look at the shadow of the Sun below a tree, you can see an image of the crescent Sun. it's the same physics as a pin-hole camera.
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It's the most magical time of the year — when estimates of last year's global average temperature anomaly come out. Time to dust off my "last year was hot" auto-response.
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Dear reporters: At this point, you should assume that every severe heat wave has been made worse by climate change — that should now be the null hypothesis.
If someone wants to argue that climate change played no role, the burden of proof is on them.
Signed,
climate science
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Quick 🧵 on wet bulb temperature and why it matters for human survivability.
To understand this, first some facts about the human body. To survive, humans need to keep their body temperature within a few degrees of 98°F.
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I have some very bad news about the rest of your life
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Senator Cornyn: I'm a climate scientist at Texas A&M. I'd be happy to explain why, even though it's summer, July's temperatures were extreme — and how we know humans are responsible. I'd be happy to put together a briefing for and/or your staff.
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My 8th grader just came to me for help with his science homework — he asked me if I knew what El Nino was. I excitedly told him to have a seat while I opened a powerpoint file with 200 slides ...
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Prediction of the future from 1982 by
@exxonmobil
, along with data showing how it has actually evolved. Exxon's predictions were extremely accurate.
#ExxonKnew
@GeoffreySupran
@NaomiOreskes
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if you think trees are a good place to sequester carbon, I recommend you look at the Canadian wildfire map.
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The other cherry pick is only looking at the U.S. Let's look at the plot for the entire northern hemisphere mid-latitudes (29N-60N). The occurrence of hot days explodes after about 1980.
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So what's going on? This is what we call cherry picking. Cherry picking is when you analyze a small amount of data to reach a conclusion that the full data set does not support.
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Some things seem to always be true.
Arguments over 1.5°C or 2°C are waste of time. We have no idea how hard it is to reduce emissions – so we need to just start cutting.
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Calls/emails from reporters asking for a comment on last's years temperature are coming earlier than normal this year. Time to dust off my "last year was hot" auto-response.
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I made this plot to convey how humans are changing the climate. This plot shows 35,000 years. Future projections are from a SSP2-45-like trajectory.
The pink band shows the fossil fuel era, which will last just a few centuries — just a brief spark in the history of humanity.
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Then, for each year, we count the number of exceedances in all grid cells in the domain. This is what the time series looks like for the U.S. Yes, the 1930s were hot, but hot days occur more frequently in the 2010s.
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tl;dr: This is classic cherry picking: the plot cherry picks an unusual metric and also cherry picks a particular region. Examining the full data set shows the opposite of what's claimed.
Temperatures and heatwaves are certainly worse today than in the 20th century.
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If you think, "solar and wind are poor energy sources because the wind doesn't always blow and the Sun goes down at night," you're thinking about it wrong. A 🧵:
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With 1.1°C of global-average warming, we are departing the climatic conditions that much of the infrastructure designed in the 20th century was designed for.
Every 0.1°C of warming is going to push us past an exponentially increasing number of thresholds in the climate system.
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I've been collecting "lessons I've learned communicating climate on Twitter" over the last 8 years and finally thought I'd write a 🧵. This is mainly aimed at younger scientists, but others might find it useful.
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"climate scientists are exaggerating the impacts of climate change"
[the planet Earth]: "Hold my beer"
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There's nothing intrinsically wrong with this definition, but it sure seems arbitrary. Why 4 days? Why 1-in-10 events?
When doing science, you should always be worried that arbitrary decisions (e.g., thresholds in an index) will give you arbitrary results.
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There's a tragic disease spreading around twitter, known by the experts as Renewable Derangement Syndrome (RDS).
You might be a carrier! Let's look at the symptoms:
🧵
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If you hear a TV meteorologist talk about climate change & make a connection to severe weather, send them an email to them saying, "Good job!" I can assure you they get a lot of crap from nutbags when they draw the connection, so please give them some positive feedback.
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In a linear system, things change in straight line. If climate impacts are linear, then every 0.1°C of warming would give you the same amount of damage.
In a non-linear world, on the other hand, every 0.1°C of warming produces larger damage than the previous 0.1°C.
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I see a lot of people with Twitter climate Ph.D.’s saying that “there’s no evidence that extreme weather is getting more severe.” This is wrong.
THREAD. 1/
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One thing that my interview with Joe Rogan has shown me is how many people's understanding of renewables lags reality. One thing I said was that, some days, wind generates > 50% of TX power. Many called BS on that. I invite those people to explore the data with me.
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as we begin summer in a few days, I'm sure there'll be lots of stories celebrating (some) people's favorite season. To help editors out, here are some photos you can use to illustrate these articles.
"BBQ is a summertime tradition"
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When people say adaptation to climate change will be easy, watch how hard it will be for the Bahamas to recover. Now recognize that this is going to happen more and more frequently and you'll get a feel for how hard adaptation is going to be.
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Bonus bad news: this is what happens with 1°C of global warming. We're on track for 3°C.
Remarkable heatwave across Mexico & Texas. Temps 110+. Heat Index 120+. This map shows the upper level ridge “Heat Dome”. Maxes out at 4.5 sigma. This means in a normal “historical” climate it’s basically impossible. But climate change makes the impossible, probable.
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This just doesn't look right. The 1930s were hot in the U.S., but not that hot. And the 2010s barely show up. The first clue something is amiss was that the quantity plotted is "Heat Wave Index". That's mysteriously vague, so I decided to figure out exactly what this was.
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People who talk about the horror of wind turbine blades always forget about the 40 billion tons of CO2 we dump into the atmosphere — every year.
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This should make some sense. In a rain event, the first inch of rain does no damage, but the 20th inch of rain is going to be a catastrophe.
Climate impacts are super non-linear. The last three inches of rain did essentially all of the damage to the University. 4/
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We can therefore expect to see worse and worse impacts coming more and more frequently as the climate continues to warm.
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The reason for the non-linearity of climate impacts is that individuals and communities are impacted by climate when it passes thresholds.
Subway systems are my go-to example of non-linear climate impacts. If rising water stops 1" below the subway entrance, the impact is zero. If the water rises an additional 2", then you experience billions of dollars of damages.
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I have an article out in
@RollingStone
about economic estimates of the costs of climate change. My conclusion: no one knows how bad climate change will be or how much it will cost to solve.
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There are really two cherry picks here. First is the choice of an obscure (and frankly weird) metric. This metric almost certainly gives an answer that is opposite to what a more exhaustive set of metrics would show.
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As energy prices rise this year never forget it's due to our reliance on fossil fuels. You should blame the politicians who have stymied our transition to renewable energy. While you get poorer, they are enriched by their corporate overlords.
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Next time someone shows this plot, please respond with this thread.
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Why is Texas electricity both unreliable and expensive?
Let me tell you about some new research by my grad student, Jangho Lee.
A 🧵:
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Thresholds are designed into the system when assumptions of the climate are built into a system. For example, when you build a bridge, you build in the capability for the bridge to expand/contract in response to a range of temperatures that you expect the bridge to experience.
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I strongly disagree with those who say now is not the time to talk about the impact of climate change on hurricanes (also known as tropical cyclones, TCs).
This is exactly the time to see what our actions have brought us.
Here's what the recent IPCC report says about TCs:
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I remember when some solar panels exploded — what a disaster that was.
BREAKING: Oil production ship explodes off the coast of Nigeria
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Recursive explanation. Trying to explain to 16-year old what “cc” in gmail means:
It means carbon copy. [blank stare] OK, let’s take a step back.
It comes from the carbon paper you put between sheets in a typewriter. [another blank stare]. OK, let’s take a step back.
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fossil fuels are:
* bad for climate
* bad for air quality
* bad for economic security
* bad for national security
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There are lots of papers that correctly estimate heatwaves. E.g., check out this paper by
@sarahinscience
and S. Lewis. This is where I got the idea to use the Berkeley daily data.
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[screaming into the void] NOOOOOOOOOOOOOOOOOOOOOOOOOO!
climate deniers deny because they don't like the policy solutions.
if you try explain the science to them, they will come up with endless objections and you will NEVER convince them.
Well since you ask^^
1) Popular science coverage of climate change is extremely weak on communicating the basics. How does the climate system even work, how do we know climate change is man-made, what are the observations, how do we make them, how do we analyse them etc.
Yeah,…
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Remember: we've only had about 1.1°C of warming and are on track for 2.5 times that much. The impacts of the next 1.1°C of warming will be much, much worse.
Colorado River Reservoirs Are So Low, Government Will Delay Releases
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That's a weak response. If you know anything about climate then you know the plot looks off and you owe your audience a minimal amount of due diligence before tweeting it out.
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I've gotten some requests asking for my reaction to Ryan Maue being hired as chief scientist of NOAA. Here it is:
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Are you tired of 💩 arguments that "renewables are more expensive because they're unreliable" or "you have to pay for backup when you install renewables". Let me explain why renewables lower the cost of energy & don't require additional backup.
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If the climate varies outside that range, the bridge may have to be closed.
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In addition, other types of extreme weather are also definitely getting worse. Zero debate about that.
I see a lot of people with Twitter climate Ph.D.’s saying that “there’s no evidence that extreme weather is getting more severe.” This is wrong.
THREAD. 1/
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It's clear that Lomborg's defense will be "I was just using a plot off the EPA website." But there are lots of plots on that page and he picked the *one* that presented the message he likes.
@AndrewDessler
Wow
so you're literally saying it is not okay to use EPA data — specifically on heatwaves — to discuss heatwaves
if the data doesn't conform to what you think "looks right"
*That* is an illegitimate argument, and I think you realize
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So the question is: if you change your definition of "heat wave", would you get a different answer?
Let's find out. The most obvious thing to do is to just count the number of hot days.
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This, by the way, is what adaptation will look like in practice.
Cape Hatteras National Seashore (Seashore) has confirmed that an unoccupied house at 24265 Ocean Drive, Rodanthe, N.C. collapsed this afternoon. This is the second unoccupied house collapse of the day at the Seashore. Read more:
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This is a perfect example of the kinds of adaptation to the climate of yesterday that's built into today's world. This cable was not designed to experience the temps we had today and will need to be fixed. The costs will be imposed on society, making us poorer.
In case you're wondering why we're canceling service for the day, here's what the heat is doing to our power cables.
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People throw around warming of 2°C or 3°C this century as if it's nothing. The last ice age was about 5°C (10°F) colder than today & it was a completely different planet, w/ ice sheets covering much of N. American & sea level 300 ft lower.
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There is no result that disqualifies climate economics more than this one. 8°C warming = loss of ~10% of GDP???? As a reminder, the last ice age was about 6°C cooler than today. Now imagine changes as big as those occurring over the next century or two. This result is absurd.
Three main models estimating costs of climate (these are the ones used by Obama Admin): DICE, PAGE + FUND
Global warming has real cost, but even strong temp rises cost ~4% of GDP — not end-of-world.
Read my 2020 peer-reviewed article:
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JFC, are we still talking about this? THE ANSWER IS NO.
Can Planting a Trillion New Trees Save the World?
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Lots of people talking about air capture of CO2. Even Prez candidates. It's a great idea, but it takes a lot of energy. To understand this, let's work out the thermodynamics. [note: nerd twitter thread] 1/
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Economists estimate that, if this happened to the Earth, GDP could drop several percent.
Star devours planet!
For the first time, researchers spotted a star swallowing another planet in our galaxy. The discovery offers clues for what could happen when Earth meets its end.
By
@KashaPatel
:
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@BjornLomborg
I’m not your programmer.
Did YOU look at 2 and 3 day events? Did you look at nighttime minimum temperatures?
Did you do any additional research or did you just look at the plot and think that it agrees with your message so you’ll go with it?
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solar + wind + nuclear is 77% of Texas power right now
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About 2/3rds of global warming comes not from direct heating by CO2, but from feedbacks. The most powerful feedback is water vapor. As CO2 warms the climate, the mass of water vapor in the atmosphere increases. WV is itself a greenhouse gas, so this creates more warming.
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Here we find that the "heat wave index" counts the occurrence of 4-day heatwaves of temperatures exceeding a 1-in-10 year recurrence.
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It's time we admitted that the 97% consensus number is wrong. There is no way that 3% of climate scientists disagree with the conclusions that the Earth is presently warming, humans are mainly responsible, and future risks are serious.
Dissenters well below 1% IMHO.
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fossil fuels are driving increases in the price of electricity. more evidence that fossil fuels are an economic disaster in addition to being an environmental disaster.
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I was at a meeting the other day and made the argument that the US cannot drill our way to energy security. Someone in the audience responded that the problem was Joe Biden and the fact that he's hampering oil drilling in the U.S.
That's wrong. A 🧵 explaining why:
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Let's take Berkeley Earth's gridded daily maximum land temperature over the (approx.) continental US.
For each grid cell, find the 95th-percentile temperature from the entire time series (1880-2020) and then count the number of days each year that exceed that.
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You're probably wondering what's irritating me these days. Today it's people who confidently contend that it's going to be very very very hard to reduce emissions by rebuilding our energy infrastructure with renewable energy. A 🧵:
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Climate skeptics be like ...
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Conspiracy alert: if power goes out in TX today, the fossil-fuel propagandists are going to try to set wind up as the patsy.
Don't let them. 🧵
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You often hear that "CO2 is plant food." Let's look at what adding CO2 to the atmosphere is actually doing. These are almond trees in CA that the farmer had to cut down. The extra CO2 sure isn't helping them.
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In the last few years, I've noticed that students in my class often become fearful for their future when they see the scientific evidence for climate change. They are particularly worried that there's no hope.
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If you’re knowledge of renewable energy is a year or two old, it’s completely out of date.
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Compare this to the last solar energy spill. We all went outside and played in it.
Breaking News: Dead fish and birds are washing up on the coast of Orange County, California, after a pipeline failure on Saturday caused at least 126,000 gallons of oil to spill into the Pacific Ocean, creating a 13-square-mile slick that’s still growing.
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Your occasional reminder that economists have no idea what the impact of climate change on our economy will be. They don't even agree on the shape of the function.
From En-ROADS:
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I remember the days before Harvey hit Houston and looking at the rain forecasts and thinking, "that can't possibly be right, the model is broken." In reality, the model was *underpredicting* rainfall.
Agreed. This is the likely next climate disaster to unfold. Several model suites indicate that several feet or ~1 meter of rain will dump over Greece in the next 2-3 days
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mid-term comments on my course this semester.
"Don't don't push climate change on students if students do not believe in it."
title of course: "climate change"
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Important additional info by the expert,
@RARohde
:
@AndrewDessler
You missed a technical but very important problem with that analysis.
That analysis of heatwaves uses the raw US measurements. Prior to the 1960s the recommended observation "day" for volunteers was 6PM to 6PM.
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My views on nuclear have officially evolved. I do expect that we will need some fraction of our energy (~20%) to come from nuclear to reach a 100%-clean grid.
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for too long, climate deniers have appropriated the word "alarmist" when describing mainstream science.
it's time to take the word back.
the true alarmists are economists who invent scare stories about how expensive solving the climate problem will be.
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Look how much hotter it is today than it was in 1998.
I remember 1998. Scientists were looking at the temperature and saying, "whoa, it's really hot."
Now '98 looks downright cool.
In 20 years, we'll be looking at 2023-24 and saying "Man, I wish it were that cool again."
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"Physics is mostly guesswork," said the dude plummeting to his death after he jumped off a building. Truly, the depths of stupidity this column reveals is staggering.
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This is not the new normal. This is a preview of the new normal. The new normal is going to be much worse than this.
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If you go the EPA website, it references a 2008 CCSP report, which references a 1999 BAMS paper:
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The IPCC reports are massive & trying to distill them into two tweets is hard, but here goes:
1) The IPCC's WG1 report, on the physics of climate change, showed that climate change is progressing as predicted over the last few decades by the scientific community. No surprises.
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A hidden truth of academics: the first time you teach a class, you learn 1000x more than the students do.
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.
@BjornLomborg
asked about heat waves instead of just the raw number of hot days.
Here's the times series of occurrence heat waves warmer than the 95th percentile of heat waves for heat waves of 2-5 days (where the temperature of a heat wave is the minimum daily temperature).
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CO2 is not plant food
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Also, sorry for switching from degrees F to C in the middle of the thread. I think in degrees C, but can force myself to write in F for general US consumption. But it's hard to consistently write F. So that was a mistake. Just remember: this website is free.
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When people say we can adapt to heat with air conditioning or economists use GDP loss as a metric, they forget one important thing: this heat absolutely sucks.
If you’re lucky you can stay indoors, but is that how you want to live your life? A prisoner of extreme heat?
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