why is global warming so catastrophic? the globe has been much warmer in the past and we are all here today
1. First, you are correct, the Earth was much hotter in the past, and I haven't seen anything convincing that global warming will lead to a fundamental "runaway greenhouse" effect a la Venus that makes life as we know it on Earth unsustainable.
2. That said, a huge climate change in a relatively short amount of time could easily lead the the deaths of billions of people, with a B. One third of the human population lives within 60 miles of the coast. Rising temperatures will lead to huge portions of the planet that are currently densely populated that will no longer support humans. The resulting migrations, "resource wars", and overall increase in extreme weather events (more hurricanes, more droughts, more floods) will lead to death and misery to a huge portion of humanity.
I'm waiting for someone to figure out how to use solar + hotter temperatures + seawater to give us desalinated water
And regardless, if you think moving a third of humanity to vastly different lands will be hunky dory smooth sailing, you should study history.
This does not seem likely, the bar for a region being "unable to support humans" is very high. People already live in cities that need to support themselves with food from elsewhere, and worldwide calorie production per capita is increasing.
I feel like the problem with climate change is that by the time the effects get so bad that everyone will be on board to actually put a significant amount of resources into prevention and mitigation, it will be too late to do anything, because there is a time lag between ceasing emissions and the climate stabilizing. Additionally, all the greenhouse gasses you have already emitted are still in the atmosphere so just stopping emissions will only stop the heating up (if we are lucky) and not automatically result in the climate returning to "normal".
I hope this doesn't come across as overly-aggressive, but it seems to me like you don't really understand much about how the Dutch lived below sea levels for centuries.
Yes, over many centuries, they have built all sorts of contraptions in order to gain more land from the sea or lakes. But this is expensive, takes up a vast amount of skill and planning and is only feasible in certain terrain. The Netherlands is also a small and very rich country. To believe that the whole world can do this is complete insanity.
A huge portion of our farming is currently unsustainable. Yes, we are producing more right now, but this production is on a clock. Even without any change in climate we are screwed. Look at how many places in the world are currently undergoing water system collapse. California, a huge crop producing state, has areas that have sunk nearly 30 meters because of pumping too much water. Those same areas are highly dependant on bringing in water from long distances away. Now add unstable weather patterns the the propensity for longer droughts and tell me what you think will happen?
We are not dealing with a climate change problem. We are dealing with
A long term water supply problem
A soil salinization over vast areas problem
A soil decarbonization problem over vast areas
Increasing temperatures that are pushing our current high yield crops to their limit problem
A globalized transportation system that will quickly spread crop diseases problem
Humanity is playing russian roulette with these issues. We will get a perfect storm one of these years, for example across the midwest US being hit by a drought and crop rust and we could see a near complete failure of our corn harvest. We are talking about the potential loss of 750 million tons of calories that will rock the world to its foundations.
Sounds like a cautionary tale to our current situation.
Huge swaths of the globe will experience fatal web bulb temperatures multiple times a year by the end of the century. Very clearly this makes a region "unable to support humans".
Furthermore, a lot of the areas that will suffer from fatal wet bulb temperatures do not have the wealth to provide AC to everyone. This will drive mass migrations of people on a scale we have never seen before, destabilizing neighbouring countries (or more likely, leading to mass murder).
Finally, this is another positive feedback loop: more AC required -> more energy required -> more severe global warning.
An example of a climate effect that nobody mentioned is ocean acidification. It turned out that if you add CO2 to water, you get carbonic acid. This melts calcium carbonate at the bottom of the sea. The buffering makes the pH of the oceans relatively constant no matter what CO2 levels happen to be.
Unfortunately that buffering takes place on the order of thousands of years. Which is fine when CO2 slowly increases in level. But when it rises suddenly, as it is doing right now, the oceans turn into a mild acid. Mild, that is, except for corals and shellfish whose shells dissolve. And anything that depends on them. Which, given how ecosystems connect, is pretty much everything in the ocean.
Already, 3/4 of coral reefs in the world have experienced bleaching event. Similarly mass die-offs of shellfish have been widely reported in fisheries. Future projections are..bleak.
All of this from a level of change that would have been fine if it was spread over 10,000 years rather than 100.
Something like 40% of humans worldwide rely on fish as their primary source of protein. What happens when there's no habitat to support that food source? Mass disruptions and migrations.
So yes, the earth was warmer before, but that warming happened over geologic timeframes that allowed ecosystems to adapt and change. 100 years is long on human timescales, but it's an instantaneous disruption on geologic timescales.
And despite the convenience of your neighborhood supermarket, we are not that detached from our ecosystems. The empty shelves at the start of covid should have been a wakeup call that our supply systems are still interconnected.
If we didn't need to eat, we wouldn't be worried very much about global warming. I do need to eat, though, and I'd rather avoid having to eat global warming deniers when things get rough.
The earth was warmer in the past, but it also didn't support planet-scale agriculture of hyper-specialized, high-yield grains that are expected to feed 8+ billion people.
Moving our agriculture north doesn't work either, because of the poor quality of soil in what is currently the tundra/taiga.
If you have a handful of magic beans that will grow a magic beanstalk, that will be resistant to the temperature and weather and soil changes caused by global warming, sure, by all means, share it with us, and I'll stop worrying. We don't have that handful, though, and I'm not keen on hope-based planning.
Norway got good enough at growing things in greenhouses to be considered a breadbasket. Norway. I think you severely underestimate human adaptability.
2. You may be adaptive and want to move to some better place, but you're also just another penniless would-be immigrant with a big house loan in the country you want to leave, you don't speak the language, so what makes you think you'd be welcome in that better place?
That's always a good idea if you are an individual, and not a business.
2. I'm a penniless would-be immigrant? No, we are both captial-rich citizens of a capital-rich country in a capital-rich world capable of deploying enormous creativity and resources at incomprehensible scale to solve practical problems. Including this one, which doesn't actually require very much creativity or resources in comparison to our capabilities and needs. People predicting the doomsday love to downplay this side of economics -- the good side, the one that works. Their enormous pile of failed predictions should remind us to keep some perspective. Actual penniless immigrants? Yeah, they're going to be a problem, a big one, both in a humanitarian sense and in a cynical political stability sense. But is this the end of our civilization, or of human civilization? Not by a long shot, and claiming that it will be is crying wolf to such a shrill degree that it's an embarrassment to the cause.
[1] https://www.nationalgeographic.com/magazine/2017/09/holland-...
It's hardly surprising that such fine land becomes a breadbasket, and it's not proof that it can be done anywhere.
And you're not capital-rich if your capital is a home in an area people want to leave, and your country isn't capital-rich if people there see no future. The fine infrastructure of your former home is worthless in the eyes of the visa applicants in the country you want to move to, because they, like you, don't want to live there.
And this is assuming much at all happens. I've been watching this issue for over 30 years and no longer believe they can predict with much accuracy at all. I was quite an alarmist in 1990 but not any more.
Imagine writing a program to model this. With the interrelated variables (more CO2 means plants grow faster which uptakes more CO2. More heat means more evaporation, more small cloud cover, which means less heat. Industrial output means more air particles etc etc), the flux and all the various unknown factors (what will the energy output from the sun be in 50 years?). You mess up one small thing or make a bad assumption and it blows up. I honestly don't know how any rational person has much faith in the granular predictive power of this at all if they stop and think about it for a bit. Models are good to see how stuff works. Models at this scale to predict? Highly doubt it.
That being said, man does influence the climate to an extent it is clear. We should be cleaner. We should get off fossil fuels in an orderly fashion as they are filthy anyway. But, we don't have "12 years left to do something!". That is and always has been complete bullshit.
It's most especially annoying to hear the latest iteration of projections based on tenuous models touted as "fact" and anyone who doesn't believe is some kind of conspiracy theorist. The continual stream of failed predictions from the doom promoters is reason enough to be suspicious. The earth warms and cools. With or without us.
Finally, to all the 20 somethings turning red and mashing downvote right now, you will live long enough to see. In 30 years things will not be significantly different. Florida will still be there. There will be no mass climate migrations. The polar ice caps will still be there. There won't be a huge increase in anomalous weather events. But there will probably still be a loud group of people proclaiming "We only have 10 years to DO SOMETHING!".
It's happened numerous times before.
Consider the impact of ecosystem-related consequences others mentioned on habitability and food production. Once mass migrations and food shortages start, and starving migrants show up at the borders of higher-latitude/elevation countries in amounts orders of magnitude larger than before, what do you think will happen? Will these countries, worrying about how to feed their own citizens as crops fail due to weather anomalies, open up the borders and accept doubling their population? Will the migrants just accept being refused to enter? In the meantime, powers will be jockeying for mining rights of newly-unfrozen, but still not habitable lands. With all that pressure mounting, how long it'll take until someone starts shooting, someone else shoots back, and we'll have a WW3 on our hands?
If climate situation degrades fast enough, we'll wipe ourselves out way before the changing weather does.
1.5 million people emigrated out of a population of around 8 million.
"Of the more than 100,000 Irish that sailed to Canada in 1847, an estimated one out of five died from disease and malnutrition, including over 5,000 at Grosse Isle, Quebec, an island in the Saint Lawrence River used to quarantine ships near Quebec City. Overcrowded, poorly maintained, and badly provisioned vessels known as coffin ships sailed from small, unregulated harbours in the West of Ireland in contravention of British safety requirements, and mortality rates were high."
So some of them travelled thousands of miles while literally starving.
You can look at the map at https://www.thirteen.org/dutchny/interactives/interactive-ma... to see how much land was added. Most of lower Manhattan is built on what was ocean in 1609.
It's an engineering problem, and NYC can afford to solve it.
We weren't here then
Earth warmth comes from CO2 blanket, we can't suck it from atmosphere, we hardly can reduce CO2 production worldwide.
Also his "best case scenario" is humanity wiped from Earth ten years ago, not base case for me. "Optimistic scenario" is if world acted on current policies. And "current path" is denial (4°C–5°C raise).
To take your example from the gold smithing era. The earth warmed from -.5 -> +.6 degrees over the course of about 4000 years. We've warmed that much in the last 100 years.