Archive for the ‘Blog Article’ Category

Trump Wrongly Blamed for Destroying Sea Ice Satellite

Monday, November 6th, 2017

No, Our Ability to Monitor Sea Ice Has Not Ended

Yesterday, The Guardian ran a story with the headlines:

Donald Trump accused of obstructing satellite research into climate change
Republican-controlled Congress ordered destruction of vital sea-ice probe

But as NASA’s leader of the U.S. Science Team on one of the best satellite instruments developed for monitoring sea ice, I can tell you we will not lose our ability to monitor sea ice.

Admittedly, the premature failure of the Defense Department’s DMSP F17 and F19 satellites has definitely reduced the number of times a day we can measure the polar regions.

Artist rendering of the Defense Meteorological Satellite Program (DMSP) satellite, carrying the SSMIS instrument (upper-left) since July 1987. The unexpected failure of the F17 and F19 satellites has led to criticisms of the defunding of the final, F20 satellite in the series.

But even once a day is plenty for the purpose (sea ice doesn’t change that fast), and there are other — and better — satellites that can now do the job.

The Decision Was Made On Obama’s Watch

The first point The Guardian got wrong was that Congress’s fiscal decision to dismantle the last remaining DMSP F20 satellite was made by Congress in 2016, when Obama could have done something about it. These satellites do much more than monitor sea ice, and the decision was made knowing that we have more modern satellites that can do these jobs now. The specific sensor on that satellite that monitors sea ice, the SSMIS, is a modified microwave radiometer that was first launched in July, 1987, and was designed in the early 1980s. Because microwaves penetrate clouds, and since the polar regions are often cloudy, these window-frequency microwave radiometers have become the workhorses of sea ice monitoring.

The U.S. Long Ago Decided to Let Other Countries Take Over

I have worked with satellite microwave radiometers for 30 years now, doing NOAA and NASA sponsored research with them. The U.S. long ago made the decision to help Japan take the lead on this capability. As a result, the Japanese built the AMSR-E instrument with newer technology, more microwave channels, and higher spatial resolution to fly on NASA’s Aqua satellite in 2002. As the U.S. Science Team leader on that instrument, I and others helped Japan become a leader in producing and interpreting this kind of data.

Artist rendering of the AMSR2 instrument on the Japanese GCOM-W satellite, the new generation of climate monitoring with window frequency microwave remote sensing.

After the failure of AMSR-E in 2011, Japan launched an even better version — AMSR2 — on their own GCOM-W satellite. They are currently designing a third one for launch. Everyone in the business knows that these are expected to be the sea ice monitoring workhorses of the future, providing a daily global climate monitoring capability for a wide variety of weather and climate variables.

Other U.S. Satellites Could Help Out as Well

Even without the newer and fancier AMSR series of sea ice monitoring instruments, and even with the complete failure of the old SSMIS series of satellite instruments (many of these last much longer than their design lifetime), in a pinch we could use the window channels of the AMSU sensors flying on the NOAA polar-orbiting satellites, and the newer ATMS instruments flying on the NOAA polar orbiting satellites. The next copy of the ATMS is scheduled to be launched this Friday, November 10 on the first JPSS satellite. These instruments are not ideal for the purpose, though, and the Japanese AMSR series of sensors are expected to be the main sea ice monitoring satellites into the future.

Trump Derangement Syndrome?

One could more justifiably ask why President Obama in his 8-year term could not have asked for a dedicated climate monitoring network of global satellites. Most people don’t realize that our long-term climate monitoring with satellites has always been piggy-backed on either NOAA weather satellites, which are not designed with the stability and lifetimes needed to monitor subtle trends in climate, or on NASA one-off science experiment satellites which provide just enough data to help address specific science questions.

This is why it feels more than a little disingenuous to blame President Trump for the dismantling of a single satellite as if is going to cripple our ability to monitor climate change from space. Quoting from the Guardian article:

President Trump has been accused of deliberately obstructing research on global warming after it emerged that a critically important technique for investigating sea-ice cover at the poles faces being blocked….

This is like throwing away the medical records of a sick patient, said David Gallaher of the National Snow and Ice Data Center in Boulder, Colorado. Our world is ailing and we have apparently decided to undermine, quite deliberately, the effectiveness of the records on which its recovery might be based. It is criminal.

This claim that the Trump Administration is to blame, or that our capability is being blocked or crippled is, quite frankly, silly.

UAH Global Temperature Update for October 2017: +0.63 deg. C

Thursday, November 2nd, 2017

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for October, 2017 was +0.63 deg. C, up from the September, 2017 value of +0.54 deg. C (click for full size version):

Global area-averaged lower tropospheric temperature anomalies (departures from 30-year calendar monthly means, 1981-2010). The 13-month centered average is meant to give an indication of the lower frequency variations in the data; the choice of 13 months is somewhat arbitrary… an odd number of months allows centered plotting on months with no time lag between the two plotted time series. The inclusion of two of the same calendar months on the ends of the 13 month averaging period causes no issues with interpretation because the seasonal temperature cycle has been removed as has the distinction between calendar months.

The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 22 months are:

YEAR MO GLOBE NHEM. SHEM. TROPICS
2016 01 +0.55 +0.72 +0.38 +0.85
2016 02 +0.85 +1.18 +0.53 +1.00
2016 03 +0.76 +0.98 +0.54 +1.10
2016 04 +0.72 +0.85 +0.58 +0.93
2016 05 +0.53 +0.61 +0.44 +0.70
2016 06 +0.33 +0.48 +0.17 +0.37
2016 07 +0.37 +0.44 +0.30 +0.47
2016 08 +0.43 +0.54 +0.32 +0.49
2016 09 +0.45 +0.51 +0.39 +0.37
2016 10 +0.42 +0.43 +0.42 +0.47
2016 11 +0.46 +0.43 +0.49 +0.38
2016 12 +0.26 +0.26 +0.27 +0.24
2017 01 +0.32 +0.31 +0.34 +0.10
2017 02 +0.38 +0.57 +0.19 +0.07
2017 03 +0.22 +0.36 +0.09 +0.05
2017 04 +0.27 +0.28 +0.26 +0.21
2017 05 +0.44 +0.39 +0.49 +0.41
2017 06 +0.21 +0.33 +0.10 +0.39
2017 07 +0.29 +0.30 +0.27 +0.51
2017 08 +0.41 +0.40 +0.41 +0.46
2017 09 +0.54 +0.51 +0.57 +0.53
2017 10 +0.63 +0.67 +0.59 +0.47

The linear temperature trend of the global average lower tropospheric temperature anomalies from January 1979 through October 2017 remains at +0.13 C/decade.

Why Are the Satellite and Surface Data Recently Diverging?

John Christy and I are a little surprised that the satellite deep-layer temperature anomaly has been rising for the last several months, given the cool La Nina currently attempting to form in the Pacific Ocean.

Furthermore, the satellite and surface temperatures seem to be recently diverging. For the surface temperatures, I usually track the monthly NCEP CFSv2 Tsfc averages computed by WeatherBell.com to get some idea of how the most recent month is shaping up for global temperatures. The CFSv2 Tsfc anomaly usually gives a rough approximation of what the satellite shows… but sometimes it differs significantly. For October 2017 the difference is now +0.23 deg. C (UAH LT warmer than Tsfc).

The following charts show how these two global temperature measures have compared for every month since 1997 (except that September, 2017 is missing at the WeatherBell.com website):

Monthly comparison since 1979 of global average temperature anomalies (relative to the monthly 1981-2010 averages) between UAH LT deep-layer lower tropospheric temperature and the surface temperatures in the CFSv2 reanalysis dataset at WeatherBell.com.

As can be seen, there have been considerably larger departures between the two measures in the past, especially during the 1997-1998 El Nino. Our UAH LT product is currently using 3 satellites (NOAA-18, NOAA-19, and Metop-B) which provide independent monthly global averages, and the disagreement between them is usually very small.

While we can expect individual months to have rather large differences between surface and tropospheric temperature anomalies (due to the time lag involved in excess surface warming to lead to increased convection and tropospheric heating), some of the differences in the above plot are disturbingly large and persistent. The 1997-98 El Nino discrepancy is pretty amazing. As I understand it, the NCEP CFS reanalysis dataset is the result of collaboration between NOAA/NCEP and NCAR, and uses a wide range of data types in a physically consistent fashion. I probably need to bring in one of the dedicated surface-only datasets for further comparison…I don’t recall the HadCRUT4 Tsfc dataset having this large of disagreements with our satellite deep-layer temperatures. Unfortunately, these other datasets usually take a few weeks before they are updated with the most recent month.

…UPDATE…(fixed)…
…the 2nd of the following two plots has been fixed)…

Here’s the comparison between UAH LT and Tsfc from the HadCRUT4 dataset, through September 2017. Note that the difference with the satellite temperatures isn’t as pronounced as with CFSv2 Tsfc data, but the HadCRUT4 data has more of an upward trend:

As in the previous figure, but now CFSv2 Tsfc data has been replaced by HadCRUT4 surface data (with the latter having anomalies recalculated relative to the 1981-2010 base period).

The UAH LT global anomaly image for October, 2017 should be available in the next few days here.

The new Version 6 files should also be updated in the coming days, and are located here:

Lower Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt
Mid-Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tmt/uahncdc_mt_6.0.txt
Tropopause: http://vortex.nsstc.uah.edu/data/msu/v6.0/ttp/uahncdc_tp_6.0.txt
Lower Stratosphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tls/uahncdc_ls_6.0.txt

UAH Global Temperature Update for September, 2017: +0.54 deg. C

Monday, October 2nd, 2017

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for September, 2017 was +0.54 deg. C, up from the August, 2017 value of +0.41 deg. C (click for full size version):

Global area-averaged lower tropospheric temperature anomalies (departures from 30-year calendar monthly means, 1981-2010). The 13-month centered average is meant to give an indication of the lower frequency variations in the data; the choice of 13 months is somewhat arbitrary… an odd number of months allows centered plotting on months with no time lag between the two plotted time series. The inclusion of two of the same calendar months on the ends of the 13 month averaging period causes no issues with interpretation because the seasonal temperature cycle has been removed as has the distinction between calendar months.

The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 21 months are:

YEAR MO GLOBE NHEM. SHEM. TROPICS
2016 01 +0.55 +0.72 +0.38 +0.85
2016 02 +0.85 +1.18 +0.53 +1.00
2016 03 +0.76 +0.98 +0.54 +1.10
2016 04 +0.72 +0.85 +0.58 +0.93
2016 05 +0.53 +0.61 +0.44 +0.70
2016 06 +0.33 +0.48 +0.17 +0.37
2016 07 +0.37 +0.44 +0.30 +0.47
2016 08 +0.43 +0.54 +0.32 +0.49
2016 09 +0.45 +0.51 +0.39 +0.37
2016 10 +0.42 +0.43 +0.42 +0.47
2016 11 +0.46 +0.43 +0.49 +0.38
2016 12 +0.26 +0.26 +0.27 +0.24
2017 01 +0.32 +0.31 +0.34 +0.10
2017 02 +0.38 +0.57 +0.19 +0.07
2017 03 +0.22 +0.36 +0.09 +0.05
2017 04 +0.27 +0.28 +0.26 +0.21
2017 05 +0.44 +0.39 +0.49 +0.41
2017 06 +0.21 +0.33 +0.10 +0.39
2017 07 +0.29 +0.30 +0.27 +0.51
2017 08 +0.41 +0.40 +0.41 +0.46
2017 09 +0.54 +0.51 +0.57 +0.53

The linear temperature trend of the global average lower tropospheric temperature anomalies from January 1979 through September 2017 remains at +0.13 C/decade.

The UAH LT global anomaly image for September, 2017 should be available in the next few days here.

The new Version 6 files should also be updated in the coming days, and are located here:

Lower Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt
Mid-Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tmt/uahncdc_mt_6.0.txt
Tropopause: http://vortex.nsstc.uah.edu/data/msu/v6.0/ttp/uahncdc_tp_6.0.txt
Lower Stratosphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tls/uahncdc_ls_6.0.txt

The Monty Hall Problem: There Is No Correct Answer

Sunday, October 1st, 2017

A diversion from global warming topics.

The simple little probability problem below has apparently been debated for many years. It came to prominence when Marilyn vos Savant answered a reader’s question about it. Her answer was believed to be wrong by some of the greatest statistical minds in the world, and eventually most of them admitted she was correct after all.

A story about that debate is here.

But I maintain that the answer depends upon an unstated assumption, and so there is no correct answer. Of course, I could be wrong. Disagreeing with a person having the highest IQ in the world is, statistically speaking, not a smart thing to do.

The Monty Hall Problem

There are three doors, and behind one of them is a new car, and behind the other two doors are goats. You want the new car. You choose door #1, knowing you have a 1 in 3 chance of winning.

Monty Hall then opens door #3 and shows you a goat there. Should you change your pick from door #1 to door #2? Most people said no, that you still don’t know whether the car is behind the first or second door, and all that has happened is your chance of winning has simply improved from 1/3 to 1/2.

But Marilyn vos Savant said “yes”, that you should switch. Experts disagreed.

From what I can tell, through, it entirely depends upon why Monty Hall showed you what was behind door #3.

If there is a goat behind door #3, then clearly the new car is behind either door #1 or door #2. If Monty Hall was going to show you door #3 no matter what was behind it, then your chances are still 50/50… you might as well stay with door #1.

BUT…if Monty Hall was only going to show you a remaining door that had a goat behind it, then you should switch to door #2. The reason is you would have new information you didn’t have before…that if he knew that the new car was behind one of the remaining doors, he was going to in effect tell you that by not opening that door.

In that case, you actually have a 2 in 3 chance of winning by switching doors.

But, as far as I can tell, which of these two assumptions is in effect was never stated, and so there is no correct answer to the problem.

(RIP, Monty Hall).

The 11-Year Major Hurricane Drought: Much More Unusual than Two Cat 4 Strikes

Thursday, September 21st, 2017

Weather.com published an article noting that the two Cat 4 hurricane strikes this year (Harvey and Irma) is a new record. Here’s a nice graphic they used showing both storms at landfall.

Left: Hurricane Harvey makes landfall near Rockport, Texas, on Aug. 25, 2017 | Right: Hurricane Irma makes its first landfall at Cudjoe Key, Florida, on Sept. 10, 2017 (graphic: Weather.com).

But the statistics of rare events (like hurricanes) are not very well behaved. Let’s look at this new record, and compared it to the 11+year period of no major hurricane strikes that ended when Harvey struck Texas.

The Probability of Two Cat 4 Strikes in One Year

By my count, we have had 24 Cat 4 or Cat 5 landfalls in the U.S. between 1851 and 2016. This gives a probability (prior to Harvey and Irma) of one Cat4+ strike every 7 years. It also leads to an average return period of two Cat4+ strikes of about 50 years (maybe one of you statiticians out there can correct me if I’m wrong).

So, since the average return period is once every 50 years, we were overdue for two Cat4+ strikes in the same year over the entire 166 period of record. (Again, for rare events, the statistics aren’t very well behaved.)

The Probability of the 11-Year “Drought” in Major Landfalling Hurricane

In 2015, a NASA study was published which calculated how unlikely the (then) 9-year stretch with no major hurricane landfalls was. They came up with a 177 year return period for such an event.

I used that statistic to estimate what eventually happened, which was 11 years with no major hurricane strikes.

I get a return period of 560 years!

Now, which seems more unusual and potentially due to climate change: something that should happen only once every 50 years, or every 560 years?

Maybe global warming causes fewer landfalling major hurricanes.

Cracks in the Empire’s Armor Appear

Wednesday, September 20th, 2017

Yesterday brought widespread news coverage of a new “study” published in Nature Geoscience which concludes that global warming has not been progressing as fast as expected, and that climate models might be a “little bit” wrong.

(That the “little bit” is a factor of 2 or 3 is a fine point upon which we won’t quibble here.)

I’m still trying to process my feelings about how the two authors, Myles Allen and Michael Grubb, might have been allowed to wander so far off the Empire’s (UN IPCC’s) reservation.

My initial reaction to the news was captured by my wife:

I’ve been thinking about what led to this turn of events. I’ve decided it was not some random realization by rogue elements of the Empire. It was not a tactical anomaly, but instead a strategic trial balloon of sorts.

Had John Christy or I tried to publish such a paper, Storm Troopers led by Darth Trenberth would have been quickly dispatched to put down the rebellion.

The realization by the authors that the climate models have produced too much warming since about 2000 has been out there for at least 5 years. It has been no secret, and Christy and I have been lambasted as “deniers” for repeatedly pointing it out.

The timing of the authors’ realization of the same seems not very believable. Quoting from the Independent article,

According to The Times, another of the papers authors, Michael Grubb, a professor of international energy and climate change at University College London, admitted his earlier forecasting models had overplayed how temperatures would rise. At the Paris climate summit in 2015, Professor Grubb said: “All the evidence from the past 15 years leads me to conclude that actually delivering 1.5C is simply incompatible with democracy.” But speaking to The Times he said: “When the facts change, I change my mind, as [John Maynard] Keynes said.”

Now, I must ask, what did Grubb know, and when did he know it? What exactly has changed in the model forecasts since the Paris summit in December 2015?

Exactly nothing.

Allen and Grubb knew the models had a problem well before that.

I suspect there have been years of discussions in e-cigarette vapor-filled back rooms where Empire leaders have been discussing how the increasing disparity between models and observations should be handled. The resulting new paper is part of a grand scheme that Population Bomb author Paul Ehrlich perfected decades ago. I believe the new narrative taking shape is this: “yes, we were wrong, but only in the timing of the coming global warming disaster. It is still going to happen… but now we have time to fix it, before it really, really is too late.”

I wonder if Allen and Grubb will also be called “deniers” for pointing out that the emperor’s models have no clothes?

Only time will tell. For now, all I can say is, welcome to the dark side.

Since it is card-carrying members of the climate establishment saying the models are wrong, though, they will probably be hailed as visionaries.

Inevitable Disaster: Why Hurricanes Can’t Be Blamed On Global Warming

Monday, September 18th, 2017

Partly in response to the crazy claims of the usual global warming experts (Stevie Wonder, Beyoncé, Jennifer Lawrence, Mark Ruffalo, Bill Nye the Science Guy, Neil deGrasse Tyson, Pope Francis), I decided to write another Kindle e-book. This one is entitled, Inevitable Disaster: Why Hurricanes Can’t Be Blamed On Global Warming.

In it I review the many fascinating examples of major hurricane landfalls in the United States, even going back to colonial times.

For example, two major hurricane strikes endured by the Massachusetts Bay Colony, in 1635 and in 1675, have yet to be rivaled in more modern times. Major hurricane Maria, now approaching Dominica and Guadeloupe, is probably no match for the Great Hurricane of 1780 in the Caribbean, which had estimated winds of 200 mph and killed 20,000 people.

I also address the reasons why Hurricane Harvey and its flooding cannot be blamed on climate change. Regarding Hurricane Irma which recently terrorized Florida, you might be surprised to learn that it is consistent with a downward trend in both the number and intensity of landfalling major Florida hurricanes:

But what has changed is the number of people and amount of infrastructure at risk along the Altantic and Gulf of Mexico coastlines. Before 1900, there were virtually no people residing in Florida. Now its population exceeds 20 million. Miami was incorporated in 1896…with only 300 people. Even if there is no long term change in hurricane activity, hurricane damage will increase as coastal development increases.

I review the science of why major hurricanes in the tropical Atlantic, Caribbean, and Gulf of Mexcico are not limited by sea surface temperatures, which are warm enough every hurricane season to support catastrophic hurricanes.

Even the IPCC has low confidence in whether hurricanes will become more frequent or more severe in the coming decades. NOAA’s GFDL says we might see 2% to 11% increase in activity by the end of the century. Does that sound like what you should be worrying about during hurricane season if you live on the Florida coast? Maybe instead you should worry that you chose to live somewhere that will, inevitably, be hit by a hurricane sent by Mother Nature that will be catastrophic with or without the help of humanity’s greenhouse gas emissions.

The book is an easy read, with fewer than 11,000 words, and 17 illustrations.

UAH Global Temperature Update for August, 2017: +0.41 deg. C

Tuesday, September 5th, 2017

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for August, 2017 was +0.41 deg. C, up somewhat from the July, 2017 value of +0.29 deg. C (click for full size version):

Global area-averaged lower tropospheric temperature anomalies (departures from 30-year calendar monthly means, 1981-2010). The 13-month centered average is meant to give an indication of the lower frequency variations in the data; the choice of 13 months is somewhat arbitrary… an odd number of months allows centered plotting on months with no time lag between the two plotted time series. The inclusion of two of the same calendar months on the ends of the 13 month averaging period causes no issues with interpretation because the seasonal temperature cycle has been removed as has the distinction between calendar months.

The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 20 months are:

YEAR MO GLOBE NHEM. SHEM. TROPICS
2016 01 +0.55 +0.72 +0.38 +0.85
2016 02 +0.85 +1.18 +0.53 +1.00
2016 03 +0.76 +0.98 +0.54 +1.10
2016 04 +0.72 +0.85 +0.58 +0.93
2016 05 +0.53 +0.61 +0.44 +0.70
2016 06 +0.33 +0.48 +0.17 +0.37
2016 07 +0.37 +0.44 +0.30 +0.47
2016 08 +0.43 +0.54 +0.32 +0.49
2016 09 +0.45 +0.51 +0.39 +0.37
2016 10 +0.42 +0.43 +0.42 +0.47
2016 11 +0.46 +0.43 +0.49 +0.38
2016 12 +0.26 +0.26 +0.27 +0.24
2017 01 +0.32 +0.31 +0.34 +0.10
2017 02 +0.38 +0.57 +0.19 +0.07
2017 03 +0.22 +0.36 +0.09 +0.05
2017 04 +0.27 +0.28 +0.26 +0.21
2017 05 +0.44 +0.39 +0.49 +0.41
2017 06 +0.21 +0.33 +0.10 +0.39
2017 07 +0.29 +0.30 +0.27 +0.51
2017 08 +0.41 +0.40 +0.41 +0.46

The linear temperature trend of the global average lower tropospheric temperature anomalies from January 1979 through August 2017 remains at +0.13 C/decade.

NOTE: In June 2017 we added the Metop-B satellite to the processing stream, with data since mid-2013. The Metop-B satellite has its orbit actively maintained, so the AMSU data from it does not require corrections from orbit decay or diurnal drift. As a result of adding this satellite, most of the monthly anomalies since mid-2013 have changed, by typically a few hundredths of a degree C.

The UAH LT global anomaly image for August, 2017 should be available in the next few days here.

The new Version 6 files should also be updated in the coming days, and are located here:

Lower Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt
Mid-Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tmt/uahncdc_mt_6.0.txt
Tropopause: http://vortex.nsstc.uah.edu/data/msu/v6.0/ttp/uahncdc_tp_6.0.txt
Lower Stratosphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tls/uahncdc_ls_6.0.txt

Houston Area Flooding Seen from Space

Thursday, August 31st, 2017

Today the skies cleared enough to see the huge amount of water flowing out of southeast Texas and Houston into the Gulf of Mexico.

Here is a before-and-after animation which shows the change from July 28 versus today (August 31), taken from the MODIS imager on NASA’s Terra satellite. Click on the image to enlarge and animate it.

Turbid water is seen flowing out up to 30 miles from the coast, with a huge plume exiting Galveston Bay.

Texas Major Hurricane Intensity Not Related to Gulf Water Temperatures

Tuesday, August 29th, 2017

As the Houston flood disaster is unfolding, there is considerable debate about whether Hurricane Harvey was influenced by “global warming”. While such an issue matters little to the people of Houston, it does matter for our future infrastructure planning and energy policy.

Let’s review the two basic reasons why the Houston area is experiencing what now looks like a new record amount of total rainfall, at least for a 2-3 day period over an area of tens of thousands of square miles.

1) A strong tropical cyclone, with access to abundant moisture evaporated off the Gulf of Mexico, and

2) Little movement by the cyclone.

These two factors have conspired to create the current flooding catastrophe in Houston. Now let’s look at them in the context of global warming theory.

1. Are Texas major hurricanes dependent on an unusually warm Gulf?

I examined all of the major hurricane (Cat 3+) strikes in Texas since 1870 and plotted them as red dots on the time series of sea surface temperature variations over the western Gulf of Mexico. As can be seen, major hurricanes don’t really care whether the Gulf is above average or below average in temperature:

Red dots indicate years of major hurricane strikes in Texas, plotted on average SST departures from normal by year over the western Gulf of Mexico (25-30N, 90-100W). Note I included Hurricane Ike in 2008, which was barely below Cat3, but had a severe impact.

Why is that? It’s because hurricanes require a unique set of circumstances to occur, and sufficiently warm SSTs is only one. (I did my Ph.D. dissertation on the structure and energetics of incipient tropical cyclones, and have published a method for monitoring their strength from satellites).

The Gulf of Mexico is warm enough every summer to produce a major hurricane. But you also usually need a pre-existing cyclonic circulation or wave, which almost always can be traced back to the coast of Africa. Also, the reasons why some systems intensify and others don’t are not well understood. This is why the National Hurricane Center admits their predictions of intensity change are not that accurate. Lots of thunderstorm complexes form over warm tropical waters, and we still don’t understand why some of them will spontaneously form a cyclonic circulation.

2. Does global warming cause landfalling hurricanes to stall?

I don’t know of any portion of global warming theory that would explain why Harvey stalled over southeast Texas. Michael Mann’s claim in The Guardian that it’s due to the jet stream being pushed farther north from global warming makes me think he doesn’t actually follow weather like those of us who have actual schooling in meteorology (my degree is a Ph.D. in Meteorology). We didn’t have a warm August in the U.S. pushing the jet stream farther north.

In fact, I dare anyone to look at the August temperature anomalies to date in the U.S. (courtesy of Weatherbell.com) and tell me, exactly what pattern here is due to global warming?

August 2017 (through Aug. 28) surface temperature anomalies around North America (NCEP CFSv2, courtesy of Weatherbell.com).

The flooding disaster in Houston is the chance occurrence of several factors which can be explained naturally, without having to invoke human-caused climate change. We already know that major landfalling hurricanes in the U.S. have been less frequent in recent decades. But once one forms, if it stalls near the coast (a rarity), it can be expected to cause a flooding disaster…especially in a flood-prone area like Houston.

NOTE: If you like my writing on this subject, please check out my new e-book, An Inconvenient Deception: How Al Gore Distorts Climate Science and Energy Policy.

Posted by Rush Limbaugh’s “artificial climatologist”. Ha-ha.