We can't say Hurricane Harvey caused climate science deniers but it certainly worsened them

Harvey. Credit: NASA

Science deniers were so put out by the deadly rains from Hurricane Harvey that they lost their sense of sight. Now we can't say that Hurricane Harvey caused climate science deniers, they've existed since we changed climate in a big way. We can say that Hurricane Harvey hasn't improved them.

Joe Bastardi, a science denying weather forecaster, got all excited and wrote a dumb article that was copied and pasted in the deniosphere. Danny Hayes first alerted us here at HotWhopper. It took some time before it was copied and pasted at WUWT (archived here). It was in response to an article in the Guardian, by Professor Michael Mann. The Guardian article had the following:

In case you're a science denier, let me repeat that headline and sub-head:

It's a fact: climate change made Hurricane Harvey more deadly

We can’t say that Hurricane Harvey was caused by climate change. But it was certainly worsened by it

In the article, Professor Mann explains why the flooding from Harvey was worsened:

• Sea level rise - partly from climate change and partly from subsidence
• Higher sea surface temperatures meant more moisture in the atmosphere
• Higher sub-surface sea temperatures gave even more fuel to Harvey

In addition to the above factors, Professor Mann put forward two other factors why the storm stalled and hung about for days. One that has been predicted in models, and the other, which he said was more tenuous, but appears to be a factor in this case, and has been described previously in the scientific literature.

The first pattern:

The stalling is due to very weak prevailing winds, which are failing to steer the storm off to sea, allowing it to spin around and wobble back and forth. This pattern, in turn, is associated with a greatly expanded subtropical high pressure system over much of the US at the moment, with the jet stream pushed well to the north. This pattern of subtropical expansion is predicted in model simulations of human-caused climate change.

The second, if more tenuous pattern, that resulted in Harvey stalling and dumping so much water over Texas, was described in a recent paper in Scientific Reports:

More tenuous, but possibly relevant still, is the fact that very persistent, nearly “stationary” summer weather patterns of this sort, where weather anomalies (both high-pressure dry hot regions and low-pressure stormy/rainy regions) stay locked in place for many days at a time, appears to be favoured by human-caused climate change. We recently published a paper in the academic journal Scientific Reports on this phenomenon.

The last paragraph emphasises that it's not possible to say that Harvey was "caused" by climate change (who knows if that particular hurricane would have appeared at this particular time without climate change). What can be said is that the impact of Harvey was made worse by climate change. He wrote:

In conclusion, while we cannot say climate change “caused” Hurricane Harvey (that is an ill-posed question), we can say is that it exacerbated several characteristics of the storm in a way that greatly increased the risk of damage and loss of life. Climate change worsened the impact of Hurricane Harvey.

A strawman from Joe Bastardi and Anthony Watts

Joe Bastardi and Anthony Watts decided to build a strawman. The ludicrous nature of their attempt was immediately apparent. You'll recall how the Guardian article had in the sub-headline and the article, that "We can’t say that Hurricane Harvey was caused by climate change."  So what was Anthony and Joe's headline? Look and see.

Michael Mann’s claims that Harvey was caused by global warming are destroyed by an operational meteorologist

Michael Mann specifically wrote that we can't say that (it's an ill-posed question).  Not only did Anthony and Joe base their article on a lie of a strawman, they even had evidence their article was a lie, right up top. The article even had a picture of the Guardian headline that showed that Anthony and Joe had built a strawman:

The really strange thing is that Joe Bastardi put up a quote from Michael Mann, then proceeded to say that what he wrote was wrong, while simultaneously showing that what Professor Mann wrote was right.

This is what Joe quoted from Mann's Guardian article:

The stalling is due to very weak prevailing winds, which are failing to steer the storm off to sea, allowing it to spin around and wobble back and forth. This pattern, in turn, is associated with a greatly expanded subtropical high pressure system over much of the US at the moment, with the jet stream pushed well to the north. This pattern of subtropical expansion is predicted in model simulations of human-caused climate change.

Joe then put up this image of the weather pattern, which I've annotated showing the patterns that Dr Mann referred to:

Here's a video explaining how Harvey was blocked to the west and the east by high pressure systems, and how the jet stream, which would otherwise have pulled it north east, was too far north to do so. This is almost identical to what Michael Mann wrote.

How Joe Bastardi claims he'd have done what Michael Mann did

The other oddity is that Joe Bastardi wrote what he would have pointed to, which is exactly what Michael Mann did say. Joe wrote:

Now if it’s me, I would be talking about the warmth of the oceans. 

Compare that to what Dr Mann wrote at The Guardian:

Sea surface temperatures in the area where Harvey intensified were 0.5-1C warmer than current-day average temperatures, which translates to 1-1.5C warmer than “average” temperatures a few decades ago. That means 3-5% more moisture in the atmosphere.

About that accurate forecast from Michael Mann

What about Joe chastising Dr Mann for not making a forecast? Well, Joe mustn't follow Michael Mann on Twitter because Joe wrote:

But what is despicable is what I see coming out. If Dr. Mann was out on a limb before the season showing what he thought, or even earlier this week, that is one thing, But this is an example of what will be a relentless tirade of statements Say nothing, make no forecast you can actually be held accountable for, then come out after and grab headlines with stuff like this. 

Here is what Michael Mann tweeted before Harvey made landfall, while it was still "only" a Category 2 hurricane, forecast for maybe Category 3:

I have a bad feeling about #Harvey. Wouldn't be surprised if we wake up to a cat 4...

— Michael E. Mann (@MichaelEMann) August 24, 2017

Now that was tweeted at 8:04 am 25 August Australian time, which was about 6:04 pm 24 August US east coast time. Here's an NOAA animation of the path of Harvey. There was also this:

Super warm Gulf surface waters means more moisture and potential for excessive rainfall. Make no mistake: Climate change is part of this...

— Michael E. Mann (@MichaelEMann) August 24, 2017

By contrast, this is what Joe tweeted not long before Harvey struck:

CLIMATE HYSTERIA WATCH IN EFFECT. Will go to a warning as soon as events happen or after they do, as thats when hysterics wake up

— Joe Bastardi (@BigJoeBastardi) August 22, 2017

In my view, Joe Bastardi's view is not that different to Michael Mann's description. He just wanted to pick a fight, because he doesn't want to "believe" that we have influenced weather. Just the same, he doesn't and can't deny that warmer waters fueled the hurricane, affected the amount of rain dropped onto Texas and Lousiana, or that the jet stream wasn't far enough south to pull Harvey further north east.

For the record, at the time when I saw this next tweet I thought maybe Eric Holthaus' prediction was too ominous. It turns out to have been conservative:

Just-completed GFS model (12Z) shows nothing less than a flooding catastrophe for Texas. 24-48" of rain in 3 or 4 days.
Please pay attention pic.twitter.com/VWmOe1DtG7

— Eric Holthaus (@EricHolthaus) August 23, 2017

Harvey dangers go beyond death by drowning or wind, losing your home and business to floods, and not being able to get about. It affects drinking water, and causes chemical plants to explode, and a whole lot more, as described in this article at the Washington Post.

From the WUWT comments

Philip Clarke pointed out the fact that the Guardian headline said the opposite of what Joe and Anthony claimed. He wrote:

August 31, 2017 at 9:33 am
WUWT Headline: “Michael Mann’s claims that Harvey was caused by global warming are destroyed by an operational meteorologist”
Guardian Headline: “We can’t say that Hurricane Harvey was caused by climate change.”
Tosh of the day.
As for Bastardi, tl;dr as usual.

garyh845 thinks it doesn't matter what was written, it's what he thinks they wanted to write that matters. That's conspiracy nuttery at work.

August 31, 2017 at 10:20 am
“Guardian Headline: “We can’t say that Hurricane Harvey was caused by climate change.””
But, they really do want to say that.

Richard couldn't be bothered reading the Guardian article for the answer to his question, let alone a scientific paper:

August 31, 2017 at 9:35 am
Soooo……global warming forced Harvey to stall out and flood Texas, not because of intensity but because of lack of movement?
How does that work?

Jim Steele seems to think that Harvey was so horrible because of cooler gulf waters. He knows as much about hurricanes as he does about coral - that is, nothing. He posted an image of temperatures, not of the gulf itself, just the coastline and a link to a paper from 2015, which was a study of global coastal SST from 1982 to 2013. Yep, the data stopped four years ago!

August 31, 2017 at 9:38 am
Not to mention Gulf Coast waters have cooled since 1998 

This animation is for Jim, so that he knows that warmer sea surface temperatures fuel hurricanes. It's from NOAA and shows the temperature anomaly in Celsius, from 17 August through to 31 August. Temperatures were up to 1.5 or 2 C higher. You can also see in the last two frames how Harvey cooled the sea surface after it churned things up.

There was a lot of nastiness toward Professor Mann, as intended by Joe Bastardi and Anthony Watts. Maybe he was unaware that Michael Mann did express alarm before Harvey hit, because Tom Judd wrote:

August 31, 2017 at 3:15 pm
Perhaps, with his acute awareness of the AGW modified characteristics of hurricanes, Michael Mann should’ve shared this expertise with the Houston mayor and convinced him to evacuate the city after all. But, then again it’s always less risky to prognosticate after the fact. And, of course, it’s not inconceivable that the only evacuations Michael Mann really should be involved with are those from his lower intestines. Unfortunately, however, those evacuations always seem to be more common leaving his body from his mouth

Mary Brown wants what she'll never get. As if Michael Mann would lower himself to debate someone like Joe Bastardi. It would be like an astronaut debating a flat earther whether the world was round or flat.

August 31, 2017 at 10:15 am
Joe Bastardi and I go way back to Penn State days. He is crazy as hell… in a good way. And he calls it like he sees it. We have often disagreed over forecasting greatly but I’ve seen the utmost integrity from him in a moment when no one was watching. I’ll always remember that.
We are both now appalled that Michael Mann slithers through the halls of our formerly beloved University.
I would pay good pay-per-view money to watch the two in a MMA cage… or maybe more appropriately, a televised debate on climate change. 

garyh845 doesn't understand what he's read. This comment is upside down and back to front. garyh845 was referring to this article in the LA Times.

August 31, 2017 at 9:10 am
Get a load of this. The LAT’s yesterday, in an article headlined, “Catastrophic storms, once rare, are almost routine. Is climate change to blame(?),” quoted Mann saying:
“There is a good chance it would have happened anyway,” Mann wrote of Harvey in an email.
So, Mann is suggesting that absent AGW, there was a chance that Harvey would not have formed into a tropical system .. a hurricane . . a cat 4 hurricane? 

No, gary. Don't put words into his mouth that mean the opposite. Professor Mann is saying what he said, that "“There is a good chance it would have happened anyway,” Mann wrote of Harvey in an email. However, he added, “the impacts were likely greatly amplified by climate change.”

John Enns was appropriately disgusted with what goes on in the deniosphere, and said:

August 31, 2017 at 5:26 pm
Watt a bunch of bullshit. You reference Michael Mann saying that Harvey was caused by global warming warming and than quote what he actually said, that Harvey was influenced by it. Not the same thing at all.
Once in a while I’m curious enough about the broken logic behind adamant deniers to actually read one of your articles but the falsehoods are consistently right their in the first few paragraphs. In this case the title and subheading.