Probably not that much. What worries me is feedback loops like the melting permafrost, and collapse of the Amazon ecosystem. Or the loss of ice causing more sunlight to be absorbed. Or a sudden overflow of the ocean's ability to store energy (something that has been masking most of the warming so far). Things could run out of our control in a very short amount of time.
My biggest question is whether this will be the next climate crisis. There have been recent articles about how the earth's geology is cooling faster than expected. There are questions around if our planet will become a dead planet as it cools. It seems like speeding this up could be an issue, especially given how little we know.
A great positive feedback loop, no? Anthropogenic Climate Change (ACC) creates a need for more AC which in turn creates more ACC which furthers the need for more AC. Yeah I don't see this going well for the next few decades.
Source? We are destroying a lot of the negative feedback mechanisms (e.g. clearing rain forests, destroying the tundra, etc) what makes you sure we will be okay? A 4-5 degree Celsius increase in temperature is looking likely by 2100. If that is extrapolated out a few million years doesn’t seem plausible.
The main point about global warming is that it is rapid. Rapid climate change (in either direction) is bad for the obvious reason that we don't have much time to adjust.
In general, a warmer climate is good for us. We're at a geological-historical climate high right now, and it comes with lots of available farm land and pleasant temperatures. Raising it yet further, beyond anything human beings have experienced previously, is projected to bring some good things (Canada will be a huge farm!) and some bad things (malaria will spread its range massively, large increase in hurricanes). Raising it rapidly, however, gets us lots of the latter immediately, and the benefits if any emerge much more slowly.
So should we really be afraid of global warming? On the balance, I think a controlled, intentional warming might be a good idea, although I have no idea who would have the authority to say so or execute on it. Is the current out-of-control, unintended warming dangerous? Almost certainly.
http://scienceblogs.com/illconsidered/2006/02/whats-wrong-wi...
"Rapid change is the real danger. Human habits and infrastructure are suited to particular weather patterns and sea levels, as are ecosystems and animal behaviors. The rate at which the global temperature is rising today is very likely unique in the history of our species. "
Could you lay out the play-by-play on how global warming is a threat to civilization? It seems to me, at worst, a slow-motion problem that will take almost a century to unfold and perhaps force large chunks of people to relocate to other places.
I would appreciate it very much if you wouldn't read any kind of tone into my question. Straight up honest question.
The thing to worry about is the rate of change. I'm a fan of the visualization that XKCD did here: https://xkcd.com/1732/
When the rate of change is too fast, life struggles to adapt. Feedback loops are so tight that it accelerates even more. For instance, a slow permafrost melt means some trees die and rot, but new ones grow to replace them at similar rates. A fast permafrost melt means all the trees die and rot quickly. Their carbon is added to the atmosphere. The other plants and animals that depended on them lose all their habitat.
Think of climate like a car going 100 MPH. Climate change is changing the speed of the car. Do you want to be in a car that goes from 100 to 0 in 0.5 seconds, or in 20 seconds? The climate is changing quickly and we don't even have proper seat belts for everyone.
We are running past safe conditions, for civilization, human life or maybe most of (complex enough) life on Earth. We are already past some of those tipping points, even before reaching an average of 1.5C globally (specially when there are regional differences, and for arctic regions the average is more in the 4ºC area, and that is where most of the permafrost thawing happens).
And besides the known ones, there may be more tipping points that we are becoming aware of, like the increase of methane emissions from wetlands because hotter conditions, another positive feedback loop that may had been unexpected for some. And as feedback loops are becoming important protagonists on emissions over fossil carbon, things are getting out of our hands. We must do far more than just slow down if we want to survive in the long term.
I've thought a lot about climate change and it's consequences. If we trigger runaway warming through feedback loops involved permafrost and ocean (hydrates) methane - things are going to get really, really bad. This happened when ~5C degree warming from millions of years of the Siberian traps eruptions caused methane hydrates to be released into the atmosphere, triggering another ~5C warming and the greatest mass extinction on Earth, the End-Permian Extinction, also known as "the Great Dying" where 96% of marine species went extinct, and 70% of terrestrial species. Clearly if that happens, we're really in trouble. I don't know how likely that is, or what the trigger point would be. The climate today is not the same as it was 250M years ago.
On the other side of the coin, the Earth is uncomfortably cool these last few million years. We have these repeated periods of glaciation. Having Europe, Russia, Canada, and the northern US ground to dust beneath kilometers of ice would be a bit of tragedy too on a similar scale. That it's further away in the future doesn't make it less of a problem - if we're too aggressive solving climate change we could imagine a future where we have to deliberately pump methane into the atmosphere to stave off an ice age. For better or worse we seem to be at no risk of this through our ineptitude in responding to climate change.
For people worried about coral reefs dying, it happened less than 10K year ago at the end of the last ice age. Sea level rose 400ft and drowned the world's coral reefs. They bounced back, as you can see today. They will also bounce back from climate change - it will just suck in the meanwhile. There are undoubtedly things we can and will do to make it suck less, like developing heat resistant corals, planting reefs further north/south, etc.
For people worried about coastal cities being submerged, relax, you'll be dead by then. Long term, we should be moving our investment to more sustainable areas. But infrastructure doesn't last forever anyway, so I think a lot of that may occur naturally as people just stop developing new infrastructure in low-lying areas. There's no question it will cost us though.
If you're really worried about climate change for your descendants, get Canadian citizenship. That's one of the few countries likely to benefit from climate change.
So to sum up, climate change is not all bad, just mostly bad, until or unless it runs away on us, and then the doomsayers may be right for a change.
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