Occasional Thoughts on Climate Change

[GaWx]

2 hours ago, ChescoWx said:

So great to see young professional Meteorologists getting time on major networks to help start to turn the tide on the old climate alarmist fake narratives on simple cyclical weather events!!

 

 Hey Chesco,

 Maybe so. That was a disaster waiting to happen even without CC. We’ll never know for sure about the possible influence of CC on this terrible incident as well as on many other specific incidents. But CC/GW has meant ~ a 7% increase in moisture held in the air per degree C increase. So, CC does make these incidents of very heavy rains within a fairly short period more frequent overall worldwide than before.

 Tropical systems, themselves, have on average gotten slightly wetter. Another thing CC has apparently caused is a slight slowdown of average steering winds due to a lowered contrast of the temperature gradient between the tropics and Arctic. Thus, the slightly slower avg movement of slightly wetter tropical systems means more frequent extreme rainfall events from tropical systems.

[chubbs]

6 hours ago, GaWx said:

 Hey Chesco,

 Maybe so. That was a disaster waiting to happen even without CC. We’ll never know for sure about the possible influence of CC on this terrible incident as well as on many other specific incidents. But CC/GW has meant ~ a 7% increase in moisture held in the air per degree C increase. So, CC does make these incidents of very heavy rains within a fairly short period more frequent overall worldwide than before.

 Tropical systems, themselves, have on average gotten slightly wetter. Another thing CC has apparently caused is a slight slowdown of average steering winds due to a lowered contrast of the temperature gradient between the tropics and Arctic. Thus, the slightly slower avg movement of slightly wetter tropical systems means more frequent extreme rainfall events from tropical systems.

Yes, climate science predicted decades ago that the increase in precipitation due to climate change would be focused in the heaviest events and that is exactly what we are seeing. Extreme rain events are increasing much faster than precipitation as a whole. Climate change doesn't cause any one single event; but it makes individual cases worse and extreme events much more likely.

https://iacweb.ethz.ch/staff/fischer/download/etc/fischer_knutti_16.pdf

https://www.theclimatebrink.com/p/update-on-texas-flooding

 

[LongBeachSurfFreak]

8 hours ago, ChescoWx said:

So great to see young professional Meteorologists getting time on major networks to help start to turn the tide on the old climate alarmist fake narratives on simple cyclical weather events!!

 

Paid. END. OF. STORY. This is dangerous, and the exact reason people die needlessly. It’s simple physics….

[bluewave]

More extreme heavy rainfall leading to record flooding is the result of the record increasing atmospheric moisture content as the world continues to warm.

 

https://www.copernicus.eu/en/news/news/observer-copernicus-climate-change-service-tracks-record-atmospheric-moisture-and-sea

Water vapour: the invisible amplifier of global warming 

In 2024 the atmosphere held more moisture than previously recorded by a large margin. Total column water vapour—the total amount of moisture in a vertical column of air extending from the surface of the Earth to the top of the atmosphere—reached 4.9% above the 1991–2020 average, far surpassing previous highs in 2016 (3.4%) and 2023 (3.3%). 

Water vapour is Earth’s most abundant greenhouse gas, responsible for about half of the planet’s natural greenhouse effect. Unlike other greenhouse gases such as carbon dioxide (CO₂) and methane (CH4), the concentration of water vapour in the atmosphere is not directly influenced by human activities. However, water vapour concentration rises as the atmosphere warms: for every 1°C increase in atmospheric temperature, air can hold 7% more moisture. This creates a vicious cycle—warmer air absorbs more vapour, which traps more heat, further accelerating warming.   

 

 

Annual anomalies in the average amount of total column water vapour over the 60°S–60°N domain relative to the average for the 1992–2020 reference period. The anomalies are expressed as a percentage of the 1992–2020 average. Data: ERA5. Credit: C3S/ECMWF. 

 

 

“Water vapour is both a consequence and a driver of climate change,” explains C3S Director Carlo Buontempo. “In 2024, we saw this feedback loop in ‘overdrive’. Higher sea surface temperatures intensified evaporation, whilst warmer atmosphere allowed more water to be held there as vapour, adding ‘fuel’ to several extreme weather events.”   

The consequences are potentially disastrous. Increased atmospheric moisture can intensify storms and increase the intensity of the most extreme rainfall. The atmosphere knows no borders, so the potential effects are global.

[TheClimateChanger]

Morning thoughts:

 

[chubbs]

Below is precipitable water anomaly for this summer and the 1991-2020 normal. Here in  PA the atmosphere has had roughly 15% more moisture than normal this summer. 

[TheClimateChanger]

6 minutes ago, chubbs said:

Below is precipitable water anomaly for this summer and the 1991-2020 normal. Here in  PA the atmosphere has had roughly 15% more moisture than normal this summer. 

Good post. Warmer air holds more moisture. Doesn't mean it will fall as rain but certainly supercharges any storm that can tap into that moisture.  Just anecdotally, total precipitation locally hasn't been super crazy. But there have been a number of flash flood events around the region with some of these heavy, slow-moving thunderstorms.

[ChescoWx]

9 hours ago, GaWx said:

 Hey Chesco,

 Maybe so. That was a disaster waiting to happen even without CC. We’ll never know for sure about the possible influence of CC on this terrible incident as well as on many other specific incidents. But CC/GW has meant ~ a 7% increase in moisture held in the air per degree C increase. So, CC does make these incidents of very heavy rains within a fairly short period more frequent overall worldwide than before.

 Tropical systems, themselves, have on average gotten slightly wetter. Another thing CC has apparently caused is a slight slowdown of average steering winds due to a lowered contrast of the temperature gradient between the tropics and Arctic. Thus, the slightly slower avg movement of slightly wetter tropical systems means more frequent extreme rainfall events from tropical systems.

Zero evidence that any small impacts of our current warming climate change cycle has led to any disasters anywhere in the world!

[donsutherland1]

For illustrative purposes, I ran the numbers for New York City's Central Park (long climate record that goes back to 1869) to examine the connection between temperature and extreme rainfall events.

Here are New York City's extreme rainfall events (top 1%) over one day and two days (overlapping two-day events are not double counted; the higher two-day rainfall is retained while the lower one is dropped, as the focus is on extreme events):

 

Mean 30-Year Moving Average Temperature:

The Clausius-Clapeyron Equation suggests that the atmosphere holds approximately 7% more water vapor for each 1°C increase in temperature. Therefore, one would expect a meaningful coefficient of determination between temperature and extreme rainfall amounts. That's exactly what one finds. The coefficient of determination between temperature and the top 1% daily rainfall events is 0.47. For the top 1% 2-day events, it is 0.48. That means that temperature explains 47% and 48% of such events respectively with warmer temperatures translating into more frequent and/or intense extreme rainfall events (this analysis dealt with intensity of events). That's almost half of the outcome for such events. It is also what one would expect from the basic physics expressed through the Clausius-Clapeyron Equation. 

What about the frequency of extreme events (measured here as daily precipitation of 3" or more)? The chart is displayed below.

The coefficient of determination is much higher. It is 0.67. That means temperature explains two-thirds of the change/frequency in daily extreme precipitation events.

Additional factors involved in the frequency and intensity of such events include, but are not limited to ENSO, teleconnections, storm tracks, local/mesoscale dynamics, and land-use effects. Nevertheless, temperature, alone, is a major variable.

Any arguments made over Social Media that the warming climate plays virtually no role in the observed increase in extreme precipitation events (intensity and frequency) have no scientific merit. Not surprisingly, repeated attribution studies have found a direct connection to climate change where such events become more frequent and more intense, again consistent with the basic physics.

[TheClimateChanger]

4 hours ago, TheClimateChanger said:

Morning thoughts:

 

Wow? Why would @ChescoWxweenie this post? These are raw, unadjusted data collected from a number of locations with PORs of 100-150+ years, and a sizeable number of them are from rural locations - including Elkins, West Virginia, which has seen its hottest start to summer on record [and by a sizeable margin, at that]. I would have thought this data would be right up his alley, since he doesn't care for any adjustments.

[TheClimateChanger]

4 hours ago, TheClimateChanger said:

Morning thoughts:

 

 

[TheClimateChanger]

Just now, TheClimateChanger said:

 

For comparison purposes, here are 1936 & 2021 to date. These are the two hottest summers on record for the CONUS.

1936

 

2021

[TheClimateChanger]

One note on the IEM estimates, they tend to be off from the actual NCEI values. Comparing 1936 summer as a whole, they have it warmer than NCEI in many places (except the southwest, which they show as decidedly colder). I think the estimates for recent years are generally the opposite bias (i.e., a bit cooler). Either way, should come in as a very warm summer for the CONUS. Not sure we poach 2021 or 1936 though.