8 ms·

El Niño-like weather increases California precipitation in response to warming

64 points by Mz 9y ago

neuronexmachina 9y ago
Interesting, I hadn't previously known about this modeling result from the introduction: > In response to increasing concentrations of greenhouse gases (GHGs), climate models from the Coupled Model Intercomparison Project (CMIP) versions 3 and 5 indicate decreases in precipitation in the subtropics and increases in middle to high latitudes.
- pavement 9y ago
  Yup, deserts move and in some areas expand. Tropical weather moves toward the poles, or even dominates all latitudes. Tundra disappears. Ice caps disappear. Some of this depends on geography, and local terrain features. Lake effect precipitation or thermal activity against natural rock faces and outcroppings, which can change with tectonic activity. A silver lining is that new areas become eligible for rain forests, but only across geologic time scales. Not like next decade. Desertification, on the other hand, progresses sometimes within a generation. Mass death tends to move faster than flourishing growth, since growth explosions are rare outside of viral growth, algae blooms and invasive species (or biblical plagues like locusts) which tend to be bad things. Asian carp and huge jellyfish are neat, but humans dislike them, despite being generally successful amid new conditions or otherwise invasive.
ntelson1s 9y ago
On a planet with a surface ~3/4 covered in water, I've always just assumed since I was young that hotter weather would just mean more intense water cycles. Anywhere not landlocked on the wrong side of a watershed could stand to benefit from the extra humidity. Hopefully California can actually make use of this. There was recent rainfall the past couple years, but they have a long way to come in terms of infrastructure and also dealing with their eco laws at arms with building more reservoirs and other means of avoiding the fluctuating seasons of dry and wet. It reminded me constantly of John Steinbeck on the drought cycle in the Salinas Valley, “During the dry years, the people forgot about the rich years, and when the wet years returned, they lost all memory of the dry years. It was always that way.” For anyone who hasn't, I highly recommend checking out the drone footage of the Oroville dam. The scale of destruction was massive, and rumor has it even sparked a tiny gold rush after so much bedrock and sediment was churned up. http://imgur.com/gallery/mpUge http://imgur.com/gallery/mpUge
- tracker1 9y ago
  That was my thought as well... I've even heard statements that a 2 degree raise in temperatures globally could be great for food production by pushing the good growing zones outward toward more land mass... -- edit I'm not denying climate change, or that humans are a factor (even if relatively small).. I'm against pollution in general, And current projections to my understanding are about 50 years of minor cooling, followed by 150 years of warming to about 2 degrees hotter. It's not a "solved" issue. And I'm fine with anti-pollution stances and policies. I am not okay with using alarmist propaganda to sell anti-pollution, and then setting up systems to reward that behavior.
  - deleted 9y ago
    [deleted]
  - s_kilk 9y ago
    > 2 degree raise in temperatures globally could be great for food production... Bear in mind that the 2-degree figure is 2-degrees celcius __average__ global temperature, not two degrees maximum. The oceans are much cooler than land, and the further inland you go the hotter it gets, so at about 2-degrees average warming you've got maybe +3 degrees in Britain, and about +7 degrees Celcius in central USA, which would have catastrophic effects on food production. Now add in the pressure of vast numbers of people migrating North away from the equator because they're all literally starving, and you've got a formula for civilisation-ending instability. [EDIT] Also, bear in mind it's two degrees Celcius, which is about 3.6 degrees Farenheit, I've seen American friends get mixed up on that point, misjudging the severity by a factor of almost two.
matt_wulfeck 9y ago
Well which is it folks? Global warming is going to cause an extreme drought, or it's going to cause a rain bonanza? These researchers are starting to get lazy are blaming every change in the wind on warming.
- anotherturn 9y ago
  When all the answers are found, science will stop. As a scientist you cannot accept that what you know is the final answer. Our knowledge of the world around us should be constantly subjected to the closest scrutiny, because the answers we have are almost certainly incorrect, or incomplete.
  - nickh9000 9y ago
    While that's true the rest of the world does need concrete answers on questions, rather than, "We are only 95% certain that statement X is true." Basically scientific rigor is important to make good science, but that does not apply to policy and the rest of society. In other words, when making a statement that goes to the public, qualifying statements are problematic. The scientific community is at great fault for not being loud enough about the impact of global warming.
- omegaworks 9y ago
  Warming won't have a single symptom, that's why most people are moving away from calling it "warming." Global Warming has always meant the addition of stored energy in the atmosphere. "Warming" came from the the thermodynamic term for energy: heat. On the ground it means we'll see more extremes. Droughts, floods, record breaking heat and cold.
  - rednerrus 9y ago
    Isn't the posters point that two years ago when CA was in a drought, scientists were predicting 100 years of droughts thanks to climate change, now they're calling for 100 years of floods. It seems like this science may be suspect.
untangle 9y ago
TL;DR: "Although models possess uncertainties, including possible overestimation of tropical convection, our results suggest future GHG-induced warming may lead to an increase in CA precipitation." GHG = Greenhouse Gas
Aloha 9y ago
Color me a little skeptical - but I remember a big noise about how the drought that california was intensified by climate change.. I mean I guess its possible that the drought and increased rainfall are caused by the same thing. https://www.nytimes.com/2015/08/21/science/climate-change-intensifies-california-drought-scientists-say.html https://www.nytimes.com/2015/08/21/science/climate-change-in... When I look at the weather patterns California has had over the last 5-10 years, I see something that fits within the historical norms for the state.
- kbutler 9y ago
  The model projections provide enough variability to allow for virtually any result, so the results most likely to get press are emphasized. They have no predictive power.
  - KirinDave 9y ago
    I don't really understand why you'd say this. They absolutely have predictive power. This is like saying that because there are error margins that we can't take the mean and extract meaningful data from it. If that were the case, nearly all classic statistics would be powerless. Spoiler alert: it is not.
    - kbutler 9y ago
      It's because the model results project more snow and less snow. More rain and less rain. More severe weather and less severe weather. The example cited by the GP illustrates this - 2 years ago during the drought, climate models predicted continuing severe droughts for California. Now, they predict continuing increased precipitation. The results haven't actually changed, just different subsets are being reported. The global results are better than the regional results, but tend to run hotter than observations, suggesting they don't yet account for the full range of natural variability. Statistics don't help you predict a coin flip (actually I think tails is ever-so-slightly more likely) Edit: the point is not that a particular model can't make predictions. Some models will actually be correct. We just don't know which regional models are correct, and because of the range of results, they cannot all be correct. Therefore, as a whole, the regional models have no predictive power. The stock market is a good example. Lots of people make lots of money betting on their models, but lots of people lose lots of money when their model stops working. There is also a general rising trend underlying the whole system.
sitkack 9y ago
Time to move back!

64 points by Mz 9y ago

Interesting, I hadn't previously known about this modeling result from the introduction: > In response to increasing concentrations of greenhouse gases (GHGs), climate models from the Coupled Model Intercomparison Project (CMIP) versions 3 and 5 indicate decreases in precipitation in the subtropics and increases in middle to high latitudes.

pavement 9y ago
Yup, deserts move and in some areas expand. Tropical weather moves toward the poles, or even dominates all latitudes. Tundra disappears. Ice caps disappear. Some of this depends on geography, and local terrain features. Lake effect precipitation or thermal activity against natural rock faces and outcroppings, which can change with tectonic activity. A silver lining is that new areas become eligible for rain forests, but only across geologic time scales. Not like next decade. Desertification, on the other hand, progresses sometimes within a generation. Mass death tends to move faster than flourishing growth, since growth explosions are rare outside of viral growth, algae blooms and invasive species (or biblical plagues like locusts) which tend to be bad things. Asian carp and huge jellyfish are neat, but humans dislike them, despite being generally successful amid new conditions or otherwise invasive.

ntelson1s 9y ago

On a planet with a surface ~3/4 covered in water, I've always just assumed since I was young that hotter weather would just mean more intense water cycles. Anywhere not landlocked on the wrong side of a watershed could stand to benefit from the extra humidity. Hopefully California can actually make use of this. There was recent rainfall the past couple years, but they have a long way to come in terms of infrastructure and also dealing with their eco laws at arms with building more reservoirs and other means of avoiding the fluctuating seasons of dry and wet. It reminded me constantly of John Steinbeck on the drought cycle in the Salinas Valley, “During the dry years, the people forgot about the rich years, and when the wet years returned, they lost all memory of the dry years. It was always that way.” For anyone who hasn't, I highly recommend checking out the drone footage of the Oroville dam. The scale of destruction was massive, and rumor has it even sparked a tiny gold rush after so much bedrock and sediment was churned up. http://imgur.com/gallery/mpUge http://imgur.com/gallery/mpUge

tracker1 9y ago
That was my thought as well... I've even heard statements that a 2 degree raise in temperatures globally could be great for food production by pushing the good growing zones outward toward more land mass... -- edit I'm not denying climate change, or that humans are a factor (even if relatively small).. I'm against pollution in general, And current projections to my understanding are about 50 years of minor cooling, followed by 150 years of warming to about 2 degrees hotter. It's not a "solved" issue. And I'm fine with anti-pollution stances and policies. I am not okay with using alarmist propaganda to sell anti-pollution, and then setting up systems to reward that behavior.
- deleted 9y ago
  [deleted]
- s_kilk 9y ago
  > 2 degree raise in temperatures globally could be great for food production... Bear in mind that the 2-degree figure is 2-degrees celcius __average__ global temperature, not two degrees maximum. The oceans are much cooler than land, and the further inland you go the hotter it gets, so at about 2-degrees average warming you've got maybe +3 degrees in Britain, and about +7 degrees Celcius in central USA, which would have catastrophic effects on food production. Now add in the pressure of vast numbers of people migrating North away from the equator because they're all literally starving, and you've got a formula for civilisation-ending instability. [EDIT] Also, bear in mind it's two degrees Celcius, which is about 3.6 degrees Farenheit, I've seen American friends get mixed up on that point, misjudging the severity by a factor of almost two.

matt_wulfeck 9y ago

Well which is it folks? Global warming is going to cause an extreme drought, or it's going to cause a rain bonanza? These researchers are starting to get lazy are blaming every change in the wind on warming.

anotherturn 9y ago
When all the answers are found, science will stop. As a scientist you cannot accept that what you know is the final answer. Our knowledge of the world around us should be constantly subjected to the closest scrutiny, because the answers we have are almost certainly incorrect, or incomplete.
- nickh9000 9y ago
  While that's true the rest of the world does need concrete answers on questions, rather than, "We are only 95% certain that statement X is true." Basically scientific rigor is important to make good science, but that does not apply to policy and the rest of society. In other words, when making a statement that goes to the public, qualifying statements are problematic. The scientific community is at great fault for not being loud enough about the impact of global warming.
omegaworks 9y ago
Warming won't have a single symptom, that's why most people are moving away from calling it "warming." Global Warming has always meant the addition of stored energy in the atmosphere. "Warming" came from the the thermodynamic term for energy: heat. On the ground it means we'll see more extremes. Droughts, floods, record breaking heat and cold.
- rednerrus 9y ago
  Isn't the posters point that two years ago when CA was in a drought, scientists were predicting 100 years of droughts thanks to climate change, now they're calling for 100 years of floods. It seems like this science may be suspect.

untangle 9y ago

TL;DR: "Although models possess uncertainties, including possible overestimation of tropical convection, our results suggest future GHG-induced warming may lead to an increase in CA precipitation." GHG = Greenhouse Gas

Aloha 9y ago

Color me a little skeptical - but I remember a big noise about how the drought that california was intensified by climate change.. I mean I guess its possible that the drought and increased rainfall are caused by the same thing. https://www.nytimes.com/2015/08/21/science/climate-change-intensifies-california-drought-scientists-say.html https://www.nytimes.com/2015/08/21/science/climate-change-in... When I look at the weather patterns California has had over the last 5-10 years, I see something that fits within the historical norms for the state.

kbutler 9y ago
The model projections provide enough variability to allow for virtually any result, so the results most likely to get press are emphasized. They have no predictive power.
- KirinDave 9y ago
  I don't really understand why you'd say this. They absolutely have predictive power. This is like saying that because there are error margins that we can't take the mean and extract meaningful data from it. If that were the case, nearly all classic statistics would be powerless. Spoiler alert: it is not.
  - kbutler 9y ago
    It's because the model results project more snow and less snow. More rain and less rain. More severe weather and less severe weather. The example cited by the GP illustrates this - 2 years ago during the drought, climate models predicted continuing severe droughts for California. Now, they predict continuing increased precipitation. The results haven't actually changed, just different subsets are being reported. The global results are better than the regional results, but tend to run hotter than observations, suggesting they don't yet account for the full range of natural variability. Statistics don't help you predict a coin flip (actually I think tails is ever-so-slightly more likely) Edit: the point is not that a particular model can't make predictions. Some models will actually be correct. We just don't know which regional models are correct, and because of the range of results, they cannot all be correct. Therefore, as a whole, the regional models have no predictive power. The stock market is a good example. Lots of people make lots of money betting on their models, but lots of people lose lots of money when their model stops working. There is also a general rising trend underlying the whole system.

sitkack 9y ago

Time to move back!