I was reading the UN World Food Program site & came across a remarkable claim that is made in an attempt to attribute hunger to climate change. They list as a "fact" that
"Extreme weather events have increased five-fold over the past 50 years."
🤦♂️🧵
wfpusa.org/articles/14-fa
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Patrick T. Brown
@PatrickTBrown31
Ph.D. climate scientist. Co-director, Climate & Energy
Adjunct faculty (lecturer) in Energy Policy & Climate patricktbrown.org/cv/
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As is fond of saying, "Don't look for climate trends in economic loss data," or in this case, don't look for climate trends in disaster count data. This same problem is paramount in the NOAA Billion-Dollar Disaster analysis.
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I was reading the UN World Food Program site & came across a remarkable claim that is made in an attempt to attribute hunger to climate change. They list as a "fact" that
"Extreme weather events have increased five-fold over the past 50 years."
wfpusa.org/articles/14-fa
wfpusa.org/articles/14-faShow this thread
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It is a shame that the public-facing information presented by the UN does not accurately represent the findings of its own underlying reports. This is climate misinformation, and it should be identified as such.
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This means that the 5-fold increase in "disasters" must be dominated by increases in human and material exposure to weather hazards, not increases in weather hazards themselves or weather hazard intensities.
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All this is to say that any changes in storms or floods over the past 50 years are so small that they are very difficult to detect even with our best datasets and most sophisticated statistical methods.
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It's somewhat notable that the main reference they cite indicates more observations of long-term decreases in peak streamflow than long-term increases in peak flow.
ipcc.ch/report/ar6/wg1
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Here's what the UN IPCC says about observations of floods (focusing on river floods).
"there are regions experiencing increases...and regions experiencing decreases"
ipcc.ch/report/ar6/wg1
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Here's about all the UN IPCC can say about observations of convective storms.
"There is medium confidence that the mean annual number of tornadoes in the USA has remained relatively constant"
ipcc.ch/report/ar6/wg1
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Similarly, any changes in extratropical storms are small, but we expect warming to weaken extreme winds and enhance extreme rainfall by several percent.
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How is Climate Change Influencing the West Coast Storms? Warming should weaken extreme winds in storms like these, but it should enhance extreme rainfall by several percent.
thebreakthrough.org/issues/energy/
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Tropical cyclones have seen little change thus far.
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I listened to two @nytimes The Daily podcasts on topics related to climate change and hurricanes this week. Both give the overwhelming impression that we have seen substantial increases in hurricane strength/frequency. That’s just not true.
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Have floods and storms increased by anywhere near enough to account for much of the five-fold increase in disasters? Simply put, no.
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We can see that the vast majority of the disasters and thus disaster increases come from "flood" & "storm" hazards. Storms include tropical cyclones, extratropical storms, and convective storms.
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Going back to the original claim suggesting climate change has caused a five-fold increase in extreme weather events...
The five-fold increase comes from Figure 4a in the WMO report.
3165/711=4.45 so rounds to 4, not 5, but we'll let that slide.
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This is known as the "expanding bullseye effect." The same hazard, say a flood, will affect more people and do way more material ($) damage today than the same flood in the past.
journals.ametsoc.org/view/journals/
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In the framework of this schematic, increases in the risk of disasters are being dominated by increases in exposure to hazards, not increases in the hazards (extreme weather events) themselves.
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This is because global population has more than doubled since 1970, and GDP has increased by a factor of 30. So today, there are way more people, and there is way more material value in the way of any given hazard.
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More specifically, below is how a "disaster" is defined in the UN WMO report.
Changes in disasters incorporate changes in "human, material, and economic losses."
It turns out that changes in those aspects are MUCH larger than changes in weather hazards over the past 50 years.
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Why is this distinction so important? Becasue disasters can increase dramatically without hazards increasing. That's b/c the risk of a disaster is also affected by exposure (people & assets in the way of hazards), & vulnerability (how sensitive people & assets are to the hazard).
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Because
"Weather-Related Disasters" =/= "Extreme Weather Events".
In this area of research, "disasters" are defined as events that have a negative impact on people.
The weather component of the disaster (like a hurricane, flood, or drought) is referred to as the "hazard."
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Now at first glance, the World Food Progam Claim about "Extreme Weather Events" increasing five-fold seems like it's consistent with the above headline about "Weather-Related Disasters" increasing five-fold. BUT THEY ARE NOT CONSISTENT. Why?
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These headlines are covering a UN World Meteorological Organization (WMO) report called the Atlas of Mortality and Economic Losses from Weather, Climate and Water Extremes (1970–2019).
library.wmo.int/index.php?lvl=
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Let's interrogate this claim. No reference is provided, so it's not clear what they are referring to. However, If you Google the phrase "Extreme weather events have increased five fold over the past 50 years." The top results all link to another UN document. Here's an example.
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Upon closer inspection, it seems that this is just another example of an institution that *should* know better and *should* command respect (they have won a Noble Peace Prize!) getting away with publishing climate misinformation in broad daylight.
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As someone who has developed and taught a university class on changes in extreme weather under climate change, I was very surprised to see such a large number (five-fold) being claimed. It would not be consistent with any analysis I am aware of.
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I was reading the UN World Food Program site & came across a remarkable claim that is made in an attempt to attribute hunger to climate change. They list as a "fact" that
"Extreme weather events have increased five-fold over the past 50 years."
🤦♂️🧵
wfpusa.org/articles/14-fa
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begging people to stop romanticizing the pre-industrial era
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Some good news from California's recent rains: On December 22nd, 1 out of 17 major water supply reservoirs was above its historical average, and as of January 22nd, 10 out of 17 reservoirs are above their historical average. cdec.water.ca.gov/resapp/Rescond
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Sometimes our meteorology majors wonder why they must take 3 semesters of calculus & 3 semesters of calc-physics as prereqs for our upper-division classes. It is not an exercise in cruelty. Our understanding of weather systems is expressed through the language of calc & physics!
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As we head into the spring, meteorology professionals, students, and hobbyists start paying more attention to severe weather and thus Skew T Log P Sounding Diagrams. I made an explanatory video on these if you want to learn the basics or need a refresher.
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By the way, I mention in the piece that this event is unusual in recent memory. However, it is hardly without precedent if you go back further in time. For example, a much more severe version of this kind of event caused the Great Flood of 1862
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Models indicate that global warming to date has enhanced extreme 5-day rainfall totals in San Francisco by about 4%. That means the 5.5 inches of rain that fell in the first week of January would have been more like 5.3 inches in a preindustrial climate.
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How is Climate Change Influencing the West Coast Storms? Warming should weaken extreme winds in storms like these, but it should enhance extreme rainfall by several percent.
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Awesome 15-day loop of the storms impacting California put together by Mike Voss, SJSU Dept of Meteorology and Climate Sciences.
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This is my most common reoccurring dream and I’ve heard many others say that too. It never goes away apparently.
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when do I stop dreaming that I’m months into a semester and about to fail a class I forgot about? I have a phd
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Observations show that cold extremes have been getting less cold.
Models project that this will continue.
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Pre-Christmas forecasts call for fast-falling temperatures and possible bomb cyclone “because the jet stream is loopier than usual.” trib.al/Ch286dP
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Observations show that cold extremes have been getting less cold.
Models project that this will continue.
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Excellent and very timely article from . No, global warming does not make extreme cold events colder.
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thebreakthrough.org/issues/energy/
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✅ on #coldweather warming claims: "Rather than having to say, 'this cold happened in spite of #climatechange,' they get to say, 'this cold happened because of climate change.' When outlets publish [such] stories, they are jettisoning consensus climate science."
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No, global warming is not bring more extreme winters. @PatrickTBrown31 breaks down the science in this new @TheBTI analysis. thebreakthrough.org/issues/energy/
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