How Climate Change is Making Storms Stronger — Evaporation, Precipitation, Instability

With Cyclones Idai and Kenneth generating record breaking, back-to-back landfalls in Mozambique, with new studies indicating an increase in U.S. tornado activity and a general movement of tornadoes eastward, and with many air travelers recently grounded, it’s a good time to revisit climate change’s overall effects on extreme weather.

Kenneth approaches Mozambique

(Kenneth was the strongest storm to strike the north coast of Mozambique in at least the last 60 years. Packing peak 10 minute sustained winds of 130 mph, roughly equivalent to a category 4 Atlantic storm, Kenneth pushed a storm surge of 10-16 feet and dumped up to 24 inches of rain. According to reports, the storm destroyed 35,000 homes and has impacted 700,000 people. Image source: NASA Worldview.)

Warming Lands and Waters

Human-caused climate change (primarily driven by fossil fuel burning) has already warmed the Earth’s land and water (ocean) surfaces by around 1.1 degrees Celsius globally. This warming is not uniform. It is focused more on the poles — tending to generate islands of high surface temperature anomaly (variance from norms) interspersed with areas of somewhat above average to near normal temperatures along with smatterings of the occasional cooler pool.

Evaporation

In general, a warmer Earth evaporates more ocean water, lake water, river water, and land moisture into the atmosphere. This has the effect of increasing drought intensity and worsening the spread of severe wildfires. But evaporation also provides convective lift and moisture to local atmospheres. Rising columns of warm, wet air are primary ingredients for storms. Such columns of high energy air are key to both the formation and intensification of hurricanes. And a thunderstorm has at its heart a core of rapidly rising moist air (see embedded video below for more info).

(Climate change as storm intensification engine.)

Precipitation

Overall, evaporation rates tend to increase by about 8 percent over the surface of the globe for each 1 degree Celsius of global temperature increase. Since what goes up must come down, you also get an overall increase in precipitation rates across the globe of about 8 percent as well. The net effect is that when it does rain in a warming world, the rainfall tends to come in more intense bursts from taller, more moisture-rich storm clouds.

Instability

Like the mottled nature of global temperature increase, evaporation and precipitation changes in a warming world do not occur in uniformity across the globe. You get hot spots. Evaporation intensifies the most where the globe is warmest and where the globe warms more compared to past periods. Precipitation tends to intensify in trough zones — or regions where the atmosphere is relatively cooler than the surrounding air. All of this unevenness — the more rapidly rising air columns in hot zones, the heavier moisture loading, and the higher deltas between hot and cool and wet and dry zones tend to increase instability. And instability is also a major driver of storms.

Increase in tornado frequency US

(Tornado frequency and intensity has generally increased in the U.S. since 1979 even as tornadoes have tended to shift eastward. Image source: Spatial Trends in United States Tornado Frequency.)

At present, these are the atmospheric dynamics set in play by human-caused climate change. And they are likely to last for some time — worsening if the Earth continues to warm for at least another degree or two. So we’ll likely see a rising frequency of the more severe forms of weather. And it’s pretty clear that the early phase of this impact has already arrived.

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15 Comments

  1. Genomik

     /  April 29, 2019

    Glad to see you back doing the blog. More folks are catching on since back in the heyday of this but I miss the community.
    Here in California it’s been terrible, last year the Paradise fire (which Trump called Pleasures) was so bad that the smoke blanketed San Francisco for maybe 10 days. I was inside most of the time but one afternoon I was in the smoke for perhaps 3 hours and that night I felt terrible.
    And we were to the west of the fire, normally the smoke blows east from fires. Since many people died in the fire statistically I may have breathed human flesh vapors.
    Then Trump goes to Pleasures (Paradise) and has the gall to tell them the fires were caused by bad forest management alone. He said homeowners should rake their leaves more. It’s sort of true but he did not mention the 167 MILLION dead trees in the state from years of climate change caused drought.
    So even the poor souls who lost everything might still be brainwashed to not realize it’s climate change.

    Liked by 3 people

    Reply
  2. Noel Mount

     /  April 29, 2019

    What are your thoughts re the area around Newfoundland and Labrador where the cold Labrador current is in proximity to the warmer Gulf stream ? Here on Fogo Island, where I live, ( the most easterly point in N. American continent ) we still have a lingering winter… high winds and frequent storms have been the norm since october last year… more so than on the memory of local fishermen…

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    • I think that warming overall (Arctic atmosphere, and Atlantic middle and deep water facing sea fronting glaciers) will tend to increase Greenland melt. The result is that the fresh water flow is likely to enhance the present N. Atlantic cool pool through the fresh water lens effect. This will tend to increase ocean heat gain in the region while generating cooler weather south of Greenland. This is also a storm/instability generator.

      These statements are my opinions based on reading scientific reports and observations. For more hard science, I suggest you ask Dr. Stephan Rahmstorf who has been studying this region for some time now.

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      Reply
  3. Dorota Retelska

     /  April 29, 2019

    Here these scientists, one from MIT show that the strongest hurricanes increased 3fold http://www.realclimate.org/index.php/archives/2018/05/does-global-warming-make-tropical-cyclones-stronger/

    Liked by 2 people

    Reply
  4. mlp in nc

     /  April 29, 2019

    Robert,
    Appreciate the blog in addition to the video.

    Liked by 2 people

    Reply
  5. wharf rat

     /  April 30, 2019

    Liked by 2 people

    Reply
  6. mlp in nc

     /  April 30, 2019

    Rapid melting of the world’s largest ice shelf linked to solar heat in the . U. Cambridge
    https://www.sciencedaily.com/releases/2019/04/190429111835.htm

    An international team of scientists has found part of the world’s largest ice shelf is melting 10 times faster than the overall ice shelf average, due to solar heating of the surrounding ocean surface.
    Data from the instruments deployed on the mooring showed that solar heated surface water flows into the cavity under the ice shelf near Ross Island, causing melt rates to nearly triple during the summer months.
    The melting is affected by a large area of open ocean in front of the ice shelf that is empty of sea ice due to strong offshore winds. This area, known as the Ross Sea Polynya, absorbs solar heat quickly in summer and this solar heat source is clearly influencing melting in the ice shelf cavity.
    The findings suggest that conditions in the ice shelf cavity are more closely coupled with the surface ocean and atmosphere than previously assumed, implying that melt rates near the ice front will respond quickly to changes in the uppermost layer of the ocean.
    “Climate change is likely to result in less sea ice, and higher surface ocean temperatures in the Ross Sea, suggesting that melt rates in this region will increase in the future,” said Stewart.
    The potential for increasing melt rates in this region has implications for ice shelf stability due to the shape of the ice shelf. Rapid melting identified by the study happens beneath a thin and structurally important part of the ice shelf, where the ice pushes against Ross Island. Pressure from the island, transmitted through this region, slows the flow of the entire ice shelf.
    “The observations we made at the front of the ice shelf have direct implications for many large glaciers that flow into the ice shelf, some as far as 900 km away,” said Christoffersen.
    While the Ross Ice Shelf is considered to be relatively stable, the new findings show that it may be more vulnerable than thought so far. The point of vulnerability lies in the fact that that solar heated surface water flows into the cavity near a stabilising pinning point, which could be undermined if basal melting intensifies further.

    The researchers point out that melting measured by the study does not imply that the ice shelf is currently unstable. The ice shelf has evolved over time and ice lost by melting due to inflow of warm water is roughly balanced by the inputs of ice from feeding glaciers and snow accumulation. This balance is, however, depending on the stability provided by the Ross Island pinning point, which the new study identifies as a point of future vulnerability.

    Liked by 2 people

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  7. Robert in New Orleans

     /  April 30, 2019

    Drought hits Panama Canal shipping, highlights climate fears

    https://www.apnews.com/f0ab0672ca284c01b0ced4a648c48d88

    GATÚN, Panama (AP) — An intense drought related to this year’s El Nino phenomenon has precipitously lowered the level of Panama’s Gatun Lake, forcing the country’s Canal Authority to impose draft limits this week on ships moving through the waterway’s recently expanded locks.

    Liked by 2 people

    Reply
  8. Charlie

     /  April 30, 2019

    The Jetstreams are looking wildly deranged to me just now and getting worse by the day, but I’m no expert. They seem to be moving further toward the equator, breaking up more and splitting into threads, acting as heat transports possibly. Thoughts anyone?

    Liked by 2 people

    Reply
    • rhymeswithgoalie

       /  May 2, 2019

      The jet streams are powered by the temperature difference between the arctic and the mid-latitudes. A cold arctic produced a tighter, faster jet stream (aka “polar vortex”); the predicted “arctic amplification” means the arctic has warmed faster than mid-lats, reducing the temperature difference and resulting in a meandering jet stream.

      We broke the arctic, which broke the jet stream. It ain’t coming back for a very long time.

      Look up Jennifer Francis’ work.

      Liked by 2 people

      Reply
      • Charlie

         /  May 8, 2019

        “Hell is empty and all the devils are here.”
        ― William Shakespeare, The Tempest

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        Reply
        • These late eclipses in the sun and moon portend no good to
          us. Though the wisdom of nature can reason it thus and thus, yet
          nature finds itself scourg’d by the sequent effects. Love cools,
          friendship falls off, brothers divide. In cities, mutinies; in
          countries, discord; in palaces, treason; and the bond crack’d
          ‘twixt son and father. This villain of mine comes under the
          prediction; there’s son against father: the King falls from bias
          of nature; there’s father against child. We have seen the best
          of our time. Machinations, hollowness, treachery, and all
          ruinous disorders follow us disquietly to our graves.
          – King Lear, I.2

          Like

  9. Dave McGinnis

     /  May 1, 2019

    When I was in the army I was stationed in the Panama Canal Zone in the 70s. Dry season is Dec-Apr so check back in 30 days and see if there isn’t an improvement. I’m a meteorologist (ret.) not a climatologist so I just can’t rid myself of the idea that climate is the sum total of the weather occurrences. Extreme weather drives climate change, climate does not cause weather in my mind. Extreme weather is certainly increasing. Glad to see you back.

    Liked by 3 people

    Reply
  10. This new wind farm in New Zealand may not seem such a big deal, when everyone else is building wind and solar like crazy, but it’s highly significant for New Zealand, and has the potential to be one of the highest-capacity onshore wind farms in the world: they’re talking 45%:

    https://blog.planetaryecology.org/2019/05/01/a-long-time-between-drinks-mercury-will-build-the-turitea-wind-farm/

    Liked by 3 people

    Reply

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