4 ms·

Rising sea levels and deep drought seem at odds with each other, but I'm not a climate scientist. Maybe they go hand in hand?

4death4 3y ago
Why do they seem at odds with each other?
- thepasswordis 3y ago
  Because at least intuitively the panama canal seems to rely on seawater, which would seem like it is unaffected by drought, and only positively effected by sea level rise.
  - klyrs 3y ago
    > Canal locks at each end lift ships up to Gatun Lake, an artificial freshwater lake 26 meters (85 ft) above sea level, created by damming up the Chagres River and Lake Alajuela to reduce the amount of excavation work required for the canal, and then lower the ships at the other end. An average of 200,000,000 L (52,000,000 US gal) of fresh water are used in a single passing of a ship. https://en.m.wikipedia.org/wiki/Panama_Canal https://en.m.wikipedia.org/wiki/Panama_Canal
  - mongol 3y ago
    No the Panama canal passes through freshwater, and you cannot let seawater enter for ecological reasons.
  - deleted 3y ago
    [deleted]
  - fencepost 3y ago
    Keep in mind that water flows downhill free but you have to pay for pumping to go uphill. Climate change CAN impact availability of fresh water in the form of rain since warm air holds more moisture, but that's double edged - there's more evaporation from freshwater bodies as well, and the rain can be unpredictable and dangerous since some will be in the form of major storms dumping water nobody's equipped to store along with all the other storm damage.
  - HnUser12 3y ago
    Someone else linked this video and definitely helped me understand better https://www.youtube.com/watch?v=jh79YSCC8mM https://www.youtube.com/watch?v=jh79YSCC8mM
    - ProfessorLayton 3y ago
      I know the video covered that it has been tried before, but it seems like the long term solution would be to actually excavate and connect the seas. We have much better excavation technology, and would allow for much, much higher throughput than this elaborate contraption subject to climate change.
      - AlotOfReading 3y ago
        The seas aren't at the same elevation. The Pacific is a couple dozen cm higher than the Atlantic Coast, and the amount varies. Cutting the peninsula would turn into a disaster pretty quickly, even with sci fi excavation technology.
        jacquesm 3y ago
        I'm not so sure that it would make such a huge difference that it would be an immediate disaster, across that kind of distance there are plenty of examples of more elevation, what you would have is a river flowing one way instead of two rivers flowing towards the see. Not unlike any other island that the sea flows around. Or is there something in particular that would make this connection into a disaster area if that flow got started? The length of the canal is about 75 km, a few dozen cm across that distance would be on the order of 0.04 mm / meter, which is barely enough to make water flow in a particular direction.
        AlotOfReading 3y ago
        It'd be highly susceptible to erosion, and the channel wouldn't be stable. It'd either expand gradually over time with all sorts of ecological ramifications, or deposition would clog the channel constantly. Who knows, might do both depending on seasonal factors? Imagine the damage a hurricane might do to those massive cliffs, for example.
  - jacquesm 3y ago
    It's mostly above sea level.
acchow 3y ago
I'm trying to figure out why they would seem at odds to you. Can you elaborate please?
- lazyasciiart 3y ago
  Don’t know about original commenter, but I vaguely remember from high school science that seawater evaporates into the clouds and becomes rain. So if you picture it all as water going through a cycle, you’d expect there to be more water in all stages if there is more water in one?
  - deadbeeves 3y ago
    Perhaps there would be more water in total on land, but it doesn't mean it would be distributed evenly. Weather pattern changes caused by the rising sea level could mean that some areas get drought, even while standing right next to the ocean.
jjulius 3y ago
Upvoting this because it seems like they're genuinely trying to understand what's happening. They don't deserve the down votes. Edit: Even I learned this[1] from this comment chain, so it seems to me like this isn't necessarily common knowledge. [1]https://news.ycombinator.com/item?id=38255008 https://news.ycombinator.com/item?id=38255008
- mysterydip 3y ago
  Yes, I'm genuinely asking, thanks.
- lazyasciiart 3y ago
  That comment doesn’t really seem relevant to the question: it’s answering “why do you need freshwater for the canal when you have sea water”, but if I understood correctly, they asked “why is there less freshwater around when there’s more seawater?”
vkou 3y ago
1. Drought refers to lack of fresh water in a particular region. Sea level rise has next to no bearing on whether or not rain is going to fall in <some particular region>. A higher sea level does not meaningfully affect evaporation and precipitation rates. 2. Most of the sea level rise expected from conservative[1] projections of climate change will be hitting us decades and centuries from now. Sea levels have only risen by ~8 inches since 1900, but even if we stopped emitting carbon tomorrow, we would have another 3 feet to look forward to by 2100, and 4.5 more feet by 2200. 3. Storm surges[1], caused by stronger storms, caused by climate change can make low-lying coastal areas uninhabitable, without actually drowning them due to sea level rise. ---- [1] Less conservative projections are dismissed out-of-hand as alarmist, but seem to provide a better roadmap for reality than fairy tales, like the 2C warming that the Paris Accord promised us. [2] The sea level may have only gone up a few inches, but if an average worst-storm-of-the-year storm surge has gained a foot, it may be the difference between your house being fine, and having six inches of seawater in your living room for one day of every year.
- mysterydip 3y ago
  Thanks!
- Consultant32452 3y ago
  Would increasing global ocean and air temperatures lead to more water evaporating and a net increase in total rainfall of fresh water across the globe, even if it might also result in changes to where the rain falls?
  - 4death4 3y ago
    It could, or it could lead to more water being held in the air and this less rainfall.
  - vkou 3y ago
    Temperature increases can indeed have that effect. Sea level rise, in itself, would not.
jacquesm 3y ago
No, it makes perfect sense: more water in the oceans means less in circulation.
- londons_explore 3y ago
  Unfortunately, one really needs to divide it as "freshwater" "saltwater" and "ice". It's ice thats seeing the biggest declines. Freshwater is mostly just being redistributed.
- marcosdumay 3y ago
  It's less in ice. It's also probably more in circulation. Way more. But it almost certainly also means that water will circulate through different places, making sure you have both catastrophic floods and droughts.
  - jacquesm 3y ago
    Yes, that's true.
Tao3300 3y ago
The drought is probably just bad luck. They should have had a couple hurricanes go through there. Sometimes you just don't get the rain. AFAIK from news people freaking out every time there's a hurricane (good source, I know) climate change is causing more of them.

4death4 3y ago

Why do they seem at odds with each other?

thepasswordis 3y ago
Because at least intuitively the panama canal seems to rely on seawater, which would seem like it is unaffected by drought, and only positively effected by sea level rise.
- klyrs 3y ago
  > Canal locks at each end lift ships up to Gatun Lake, an artificial freshwater lake 26 meters (85 ft) above sea level, created by damming up the Chagres River and Lake Alajuela to reduce the amount of excavation work required for the canal, and then lower the ships at the other end. An average of 200,000,000 L (52,000,000 US gal) of fresh water are used in a single passing of a ship. https://en.m.wikipedia.org/wiki/Panama_Canal https://en.m.wikipedia.org/wiki/Panama_Canal
- mongol 3y ago
  No the Panama canal passes through freshwater, and you cannot let seawater enter for ecological reasons.
- deleted 3y ago
  [deleted]
- fencepost 3y ago
  Keep in mind that water flows downhill free but you have to pay for pumping to go uphill. Climate change CAN impact availability of fresh water in the form of rain since warm air holds more moisture, but that's double edged - there's more evaporation from freshwater bodies as well, and the rain can be unpredictable and dangerous since some will be in the form of major storms dumping water nobody's equipped to store along with all the other storm damage.
- HnUser12 3y ago
  Someone else linked this video and definitely helped me understand better https://www.youtube.com/watch?v=jh79YSCC8mM https://www.youtube.com/watch?v=jh79YSCC8mM
  - ProfessorLayton 3y ago
    I know the video covered that it has been tried before, but it seems like the long term solution would be to actually excavate and connect the seas. We have much better excavation technology, and would allow for much, much higher throughput than this elaborate contraption subject to climate change.
    - AlotOfReading 3y ago
      The seas aren't at the same elevation. The Pacific is a couple dozen cm higher than the Atlantic Coast, and the amount varies. Cutting the peninsula would turn into a disaster pretty quickly, even with sci fi excavation technology.
      - jacquesm 3y ago
        I'm not so sure that it would make such a huge difference that it would be an immediate disaster, across that kind of distance there are plenty of examples of more elevation, what you would have is a river flowing one way instead of two rivers flowing towards the see. Not unlike any other island that the sea flows around. Or is there something in particular that would make this connection into a disaster area if that flow got started? The length of the canal is about 75 km, a few dozen cm across that distance would be on the order of 0.04 mm / meter, which is barely enough to make water flow in a particular direction.
        AlotOfReading 3y ago
        It'd be highly susceptible to erosion, and the channel wouldn't be stable. It'd either expand gradually over time with all sorts of ecological ramifications, or deposition would clog the channel constantly. Who knows, might do both depending on seasonal factors? Imagine the damage a hurricane might do to those massive cliffs, for example.
- jacquesm 3y ago
  It's mostly above sea level.

acchow 3y ago

I'm trying to figure out why they would seem at odds to you. Can you elaborate please?

lazyasciiart 3y ago
Don’t know about original commenter, but I vaguely remember from high school science that seawater evaporates into the clouds and becomes rain. So if you picture it all as water going through a cycle, you’d expect there to be more water in all stages if there is more water in one?
- deadbeeves 3y ago
  Perhaps there would be more water in total on land, but it doesn't mean it would be distributed evenly. Weather pattern changes caused by the rising sea level could mean that some areas get drought, even while standing right next to the ocean.

jjulius 3y ago

Upvoting this because it seems like they're genuinely trying to understand what's happening. They don't deserve the down votes. Edit: Even I learned this[1] from this comment chain, so it seems to me like this isn't necessarily common knowledge. [1]https://news.ycombinator.com/item?id=38255008 https://news.ycombinator.com/item?id=38255008

mysterydip 3y ago
Yes, I'm genuinely asking, thanks.
lazyasciiart 3y ago
That comment doesn’t really seem relevant to the question: it’s answering “why do you need freshwater for the canal when you have sea water”, but if I understood correctly, they asked “why is there less freshwater around when there’s more seawater?”

vkou 3y ago

1. Drought refers to lack of fresh water in a particular region. Sea level rise has next to no bearing on whether or not rain is going to fall in <some particular region>. A higher sea level does not meaningfully affect evaporation and precipitation rates. 2. Most of the sea level rise expected from conservative[1] projections of climate change will be hitting us decades and centuries from now. Sea levels have only risen by ~8 inches since 1900, but even if we stopped emitting carbon tomorrow, we would have another 3 feet to look forward to by 2100, and 4.5 more feet by 2200. 3. Storm surges[1], caused by stronger storms, caused by climate change can make low-lying coastal areas uninhabitable, without actually drowning them due to sea level rise. ---- [1] Less conservative projections are dismissed out-of-hand as alarmist, but seem to provide a better roadmap for reality than fairy tales, like the 2C warming that the Paris Accord promised us. [2] The sea level may have only gone up a few inches, but if an average worst-storm-of-the-year storm surge has gained a foot, it may be the difference between your house being fine, and having six inches of seawater in your living room for one day of every year.

mysterydip 3y ago
Thanks!
Consultant32452 3y ago
Would increasing global ocean and air temperatures lead to more water evaporating and a net increase in total rainfall of fresh water across the globe, even if it might also result in changes to where the rain falls?
- 4death4 3y ago
  It could, or it could lead to more water being held in the air and this less rainfall.
- vkou 3y ago
  Temperature increases can indeed have that effect. Sea level rise, in itself, would not.

jacquesm 3y ago

No, it makes perfect sense: more water in the oceans means less in circulation.

londons_explore 3y ago
Unfortunately, one really needs to divide it as "freshwater" "saltwater" and "ice". It's ice thats seeing the biggest declines. Freshwater is mostly just being redistributed.
marcosdumay 3y ago
It's less in ice. It's also probably more in circulation. Way more. But it almost certainly also means that water will circulate through different places, making sure you have both catastrophic floods and droughts.
- jacquesm 3y ago
  Yes, that's true.

Tao3300 3y ago

The drought is probably just bad luck. They should have had a couple hurricanes go through there. Sometimes you just don't get the rain. AFAIK from news people freaking out every time there's a hurricane (good source, I know) climate change is causing more of them.