Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Nine climate tipping points now 'active,' warn scientists

phys.org

Post reply on HN
Print view View original

51–60 of 99 posts

Re: Nine climate tipping points now 'active,' warn scientists

#51

Post by ppf »

Sharlin wrote: post #39
ppf wrote: post #27

Earlier quoted context omitted.

Ok, I used the wrong word. I was also referring to OP's point that "nature was just fine" - the earth has been up to 12degC warmer than present, before humans could make any impact. My point is that, taken in isolation, a warmer earth is not fundamentally bad, nor new. As for his point about humans preferring warmer temperatures - hopefully that is self-evident. >As far as we know, the loss of arable land caused by t…

And the "hothouse" Earths were drastically different from Earth today. Given time, life adapts, but the point is that there's no time. There have been sudden, drastic global climate changes in Earth's history before. It's just that they have been accompanied by massive extinction events. Whatever we do, we probably won't destroy the whole ecosystem. But that's a rather ridiculously low bar to clear!

Sure, the "hothouse" earths are at the drastic end of the scale, but earth has spent significant periods of time at temperatures a few degrees above current. "There is no time" is a complex assertion that needs at least some research, and if there really isn't, what do you propose we do?

Re: Nine climate tipping points now 'active,' warn scientists

#52

Post by ppf »

whatawaste wrote: post #47
ppf wrote: post #14

Earlier quoted context omitted.

That's not very humble. His assertions are quite basic, and don't need research-grade qualifications to consider. The earth has certainly prehistorically been much warmer, so nature handled it just fine, and it is an interesting question to consider how much more arable land a warmer earth would have.

The earth has also been molten rock at one point too, the issue is can humans survive in that environment, not just the fact the earth is warmer.

The earth isn't going to return to that state any time soon :) I posed it as an open question - given any particular rise in temperature, what is the total loss and gain of inhabitable land?

Re: Nine climate tipping points now 'active,' warn scientists

#53

Post by shkkmo »

ppf wrote: post #34
orbifold wrote: post #32

Earlier quoted context omitted.

The details make it a very hard problem. There is scientific consensus that a too rapidly changing climate leads to mass extinction of species (plants, animals, etc.), because suddenly species are not adapted to the climate they find themselves in and can't migrate quickly enough. This loss of biodiversity should be of great concern, because it is irrecoverable. There are tons of other non-obvious problems that are n…

It is a very hard problem, which is why I personally hate to see so many issues conflated under one slogan. Your point about species adaption is a fair one, however if we are going to consider absolute effects on biodiversity, direct human activity has already had a significantly worse effect.

> if we are going to consider absolute effects on biodiversity, direct human activity has already had a significantly worse effect

Do you have a source for this or are you just basing it on "common sense"

It does toe that Hans have primarily impacted species that tend to sit higher on the food chain. We have caused the extinction of more animals than plants. Rapid warming can kill of plants that can't move quickly migrate quickly enough to stay within the temperature ranges where they can survive.

It isn't just matter of spreading their seeds far enough (like the reforestation of New England), many plants rely on a prexistingnset of conditions created by the the presence of other species to be able to grow. When the required shifts get large enough there simply may not be enough time for those conditions to be established elsewhere before the temperatures in the current areas kills off the species.

Plants species (and animals like coral) serve as a critical component for many other species. It is quite conceivable that rapid global warming will lead to an extinction event that far exceeds anything that humans have managed to date.

Our understanding of ecological systems is still pretty limited and I don't think we can know for sure how bad it will be. I am personally hopeful that we can delevope terraforming techniques to assist with ecosystem relocation that can mitigate some of this.

Re: Nine climate tipping points now 'active,' warn scientists

#54

Post by [deleted] »

wayoutthere wrote: post #35
ElonMuskrat wrote: post #16

Earlier quoted context omitted.

Pretty hard to take climate change reporting seriously. The media is an amplifier that only publishes the most alarmist scientific findings, always blanketed in paragraphs of the editors own apocalyptic interpretation. Climate science is complex. There's a broad spectrum of findings, many are not world-ending, and sometimes disagree on the details.

If anything, the media understates the threat by mixing in a lot of debunked misinformation. It's hard to take most journalism seriously with the sensationalism bias, but we're already seeing serious negative effects from climate change in the most vulnerable countries. The planet will be a very different place in 50 years.

[deleted]

Re: Nine climate tipping points now 'active,' warn scientists

#55

Post by Lutger »

jezenesklof wrote: post #15

"Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet." Talk about weasel words "Exiting the fossil fuel economy is unlikely before 2050, but with temperature already at 1.1°C above pre-industrial temperature, it is likely Earth will cross the 1.5°C guardrail by 2040.…

Yes, it's because the impact of putting greenhouse gas in the atmosphere is not immediate. Temperatures will continue to rise after the fact. Sea level rise is also much slower, meaning that even if we stop emitting, levels continue to rise for hundreds of years.

There's a lot of uncertainty regarding the tipping points. Some scientists fear that if we cross the 2 degrees celcius, we could have a runaway breakdown due to processes such as melted ice heating the ocean much more and permafrost releasing enormous amounts of ghg.

We don't know for sure that will happen, but its extremely risky. Some fear we could lock in devastating processes within 12 years (even if they won't happen immediately).

Some people think that even if we don't know for sure it'll happen, we should follow the precautionary principle and not take the risk of these extreme events.

Re: Nine climate tipping points now 'active,' warn scientists

#56

Post by NeedMoreTea »

ppf wrote: post #44
NeedMoreTea wrote: post #40

Earlier quoted context omitted.

A warmer earth with humans on it is fundamentally new, as we've not been around that long. Even forerunner species like Homo habilis only go back three million years. An eye blink in the geologic record, and long, long after the five mass extinctions. 12C warmer would put vast amounts of the land area of the planet outside habitable conditions for humanity. We'd probably be restricted to former arctic regions, and no…

True, it would be new to humans, but (at least initially) it's not fundamentally a problem (please note, I'm arguing in the most theoretical sense here). Large amounts of the equatorial regions are already uninhabitable - it would be interesting to see an analysis of the total inhabitable land loss vs gain for each degree in temperature rise.

Given a slow enough rate of change, species would adapt and migrate. Presuming there aren't farms, cities, roads, railways, dams and fences preventing smooth migration to the newly appropriate regions.

My concern is we're changing the climate at geologically unprecedented rates, likely far too quickly for species to evolve and migrate, even if we hadn't locked up 50% of the world's landmass for our own use. That will play interesting havoc with food chains no matter what former permafrost and arctic is freed up for use (with its own emissions load on melting).

Re: Nine climate tipping points now 'active,' warn scientists

#57

Post by vixen99 »

melonkidney wrote: post #17

One thing I find encouraging is how many people (particularly young people) are now understanding the seriousness of the climate situation. I would really like to see a public pledge from companies, universities, etc that people who risk their education/career by pushing for real change will not be disadvantaged. If anyone is interested in helping to make this a reality, shoot me an email at together@highestsupport.c…

Getting it into perspective, emissions of CO2 in the UK are now at a level last seen in 1890 and that contribution to world CO2 is around 1% with US at 16% with a bit more than half that from Europe.

https://www.carbonbrief.org/analysis-uk-carbon-emissions-in-... https://www.ucsusa.org/resources/each-countrys-share-co2-

Meanwhile it's widely understood that all major fossil fuel-producing nations—including the United States, China, Russia, Saudi Arabia, India, Canada, and Australia—have ambitious plans to increase production.

It's understanding on the part of the odd 70% that counts and good luck with that. Lectures from the West don't go down very well especially since most of these countries are committed to increasing their standard of living and that's necessarily linked to energy use.

Re: Nine climate tipping points now 'active,' warn scientists

#58

Post by torstenvl »

xienze wrote: post #48
perfunctory wrote: post #36

Earlier quoted context omitted.

> they'll change their tune Like this guy for example, right? [My hunger strike could be deadly. But I am willing to risk that for climate action] https://www.theguardian.com/commentisfree/2019/nov/27/hunger...

Yeah get back to us when he’s actually dead, which he won’t be.

I'm sorry, but is your argument really that this issue is "n[o]t thought ... through" unless people actually starve themselves over it? That it's all a "ploy" unless this guy actually dies for his cause?

I can't quite tell if you're engaging in a non sequitur or moving the goalposts, but your comment doesn't make sense to me in context.

Re: Nine climate tipping points now 'active,' warn scientists

#59

Post by ppf »

shkkmo wrote: post #53
ppf wrote: post #34

Earlier quoted context omitted.

It is a very hard problem, which is why I personally hate to see so many issues conflated under one slogan. Your point about species adaption is a fair one, however if we are going to consider absolute effects on biodiversity, direct human activity has already had a significantly worse effect.

> if we are going to consider absolute effects on biodiversity, direct human activity has already had a significantly worse effect Do you have a source for this or are you just basing it on "common sense" It does toe that Hans have primarily impacted species that tend to sit higher on the food chain. We have caused the extinction of more animals than plants. Rapid warming can kill of plants that can't move quickly mi…

I don't really have a source on that, although I'm also not aware of any particular species that are known to have been wiped out due to the current climate change. It is, however, fairly obvious that humans have had an enormous impact on pretty much every inhabitable part of the earth. Even without climate change, it's plausible that human activity will ultimately destroy most ecosystems.

>It is quite conceivable that rapid global warming will lead to an extinction event that far exceeds anything that humans have managed to date. >When the required shifts get large enough there simply may not be enough time... >Our understanding of ecological systems is still pretty limited

You've made a number of assertions here about ecology with no reference to research.

This is one of my main issues with the way climate change is presented - much is made of tipping points and the scale of the incoming catastrophe, but the fact is we simply don't know. Even if it is true that we have a low number of decades until irreversible catastrophe, what exactly can be done about that?

Re: Nine climate tipping points now 'active,' warn scientists

#60

Post by ppf »

NeedMoreTea wrote: post #56
ppf wrote: post #44

Earlier quoted context omitted.

True, it would be new to humans, but (at least initially) it's not fundamentally a problem (please note, I'm arguing in the most theoretical sense here). Large amounts of the equatorial regions are already uninhabitable - it would be interesting to see an analysis of the total inhabitable land loss vs gain for each degree in temperature rise.

Given a slow enough rate of change, species would adapt and migrate. Presuming there aren't farms, cities, roads, railways, dams and fences preventing smooth migration to the newly appropriate regions. My concern is we're changing the climate at geologically unprecedented rates, likely far too quickly for species to evolve and migrate, even if we hadn't locked up 50% of the world's landmass for our own use. That will…

Fair enough - so how are humans sustainable?
Post reply on HN