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Greenland ice sheet is close to a melting point of no return

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Re: Greenland ice sheet is close to a melting point of no return

#181

Earlier quoted context omitted.

> It doesn't seem reasonable to say we have hundreds of years to figure out a solution. We've also known about the global warming problem in great detail for well over 50 years at this point. Since then we haven't figured it out but made it worse -- most of our cumulative emissions have happened in just the last 50 years. Why do people still think we can figure this out in a matter of decades without having to drasti…

Kick the can down the road. Nothing to see here. Let our progeny figure out how to clean up the mess we created. We're doing the same thing with our debt, too. I'm just going to put it out there - our progeny is going to hate our guts. Then again, maybe afterward humanity will hold us up as an example for what not to do, how not to solve global problems. They'll be able to use history to quickly and effectively shut…

As a fairly new parent, I'm not thrilled about the world my daughter will inherit. I struggle with a lot of questions like whether I should raise her to be a "good" person or a "successful" person.

But, I've heard that studies show that younger generations are more concerned about the environment. Both in that they are showing an interest in the subject at younger ages and they are more likely than older generations to acknowledge it as an issue that affects them.

This suggests that our children may not only be better equipped to handle these issues than we are (assuming we continue to advance science and technology without major catastrophe in the meanwhile), but will be more interested in pursuing these problems both personally and professionally and, in the worst case, more willing to make the necessary sacrifices to see actual change.

While I certainly hope we can do more and that I can have some confidence my children will actually be better off than myself, changing the way the world thinks is a very slow and difficult thing to do. It may be the case the best we can accomplish is to hold it together the best we can while teaching our children to care about the world around them, and, when the time comes, step aside to let them solve these problems.

Re: Greenland ice sheet is close to a melting point of no return

#183
post #70
post #29

Earlier quoted context omitted.

No, the story is that we begin the melting by raising the earth's temperature a little. You'd think that if we reduced our carbon emissions, the ice would stop melting. > But once the ice crosses the threshold, it would inevitably continue to melt Bear in mind that the atmosphere retains carbon dioxide for ~50 years, that other melt events are dumping methane into the atmosphere from permafrost. It's not just one fac…

>You'd think that if we reduced our carbon emissions, the ice would stop melting. People think of climate change like a river. You reduce emissions, you reduce the size of the emissions, you reduce the size of the problem. But it's more like a bathtub. Emissions are the water filling the tub, but the real problem is the water level already in the tub. If you reduce emissions, you reduce the size of the flow into the…

Filling a bath tub requires active control, are you saying humans need to actively control the climate of the entire earth?

Re: Greenland ice sheet is close to a melting point of no return

#184
post #136

Earlier quoted context omitted.

> Bear in mind that the atmosphere retains carbon dioxide for ~50 years It's 300-1000 years [1]. [1] https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-...

Good thing plants eat carbon dioxide then, so we don't need to wait for it to break down by itself. The more CO2 in the atmosphere, the more plants grow and convert it to oxygen.

You can see the earth "breathing" CO2 in this data.

https://gml.noaa.gov/ccgg/trends/

The amplitude of the world's natural CO2 cycle is on par with about 1.5 years of anthropogenic emission. Which is certainly impressive, but it's cylic and fairly steady. Plants are not growing fast enough to support the fantasy you describe.

Re: Greenland ice sheet is close to a melting point of no return

#185
post #29

Earlier quoted context omitted.

No, the story is that we begin the melting by raising the earth's temperature a little. You'd think that if we reduced our carbon emissions, the ice would stop melting. > But once the ice crosses the threshold, it would inevitably continue to melt Bear in mind that the atmosphere retains carbon dioxide for ~50 years, that other melt events are dumping methane into the atmosphere from permafrost. It's not just one fac…

>have to remain elevated for hundreds of years or even longer for this feedback loop to become effective. To further reiterate: hundreds of years or even longer for this feedback loop to become effective.

Said another way, within two full human lifetimes the planets climate could further be irreversibly changed locking in 23 feet of sea level rise from Greenland alone.

Though, generally for emissions we are talking about a first order derivative. Just because you've slowed down from 100 to 50 does not mean you won't still run out of roadway.

So, if we are a hair away from that tippingpoint, and magically go to zero emissions, we'll still hit the tipping point. Hence, it's not two lifetimes, but that is the total runway left so far for this.

You can also consider the other extreme where CO2 is dumped into the atmosphere that everything shortens up. Another analogy, boil some water, put it off the burner, drop a small amount if ice in the water. The water won't cool off fast enough for the ice to not melt. It may take 10 minutes for that to happen, but the point of no return was when the water started at a boil.

Re: Greenland ice sheet is close to a melting point of no return

#186

Every time there's an article about climate change, it's always about how we're "close to the point of no return." It's felt like the Truck Almost Hitting The Pole GIF[1] for like 10 years now. Has anything actually gone past the point of no return? I'll almost be relieved when we're officially inevitably fucked... at least these "nearly there!" articles won't keep popping up. 1: https://tenor.com/view/truck-crash-te…

15 to 20 years ago the world was on the brink of collapse due to peak oil. And well that didn't happen..... I'm not trying to dismiss the climate change issue, but remember the media loves sensationalist articles, as that's what sells views. And what's more sensational than selling the story that we are on the brink of extinction?

Case in point, if you've watched the news over the past week you'd expect Paris to be a warzone with protests everywhere and the city burning to the ground. A freind visited last week, going to all the usual tourist places, and said they didn't see a single protest or building burning. There was uncollected trash though - in neat piles next to the bins.

Re: Greenland ice sheet is close to a melting point of no return

#187
post #136

Earlier quoted context omitted.

> Bear in mind that the atmosphere retains carbon dioxide for ~50 years It's 300-1000 years [1]. [1] https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-...

Good thing plants eat carbon dioxide then, so we don't need to wait for it to break down by itself. The more CO2 in the atmosphere, the more plants grow and convert it to oxygen.

The carbon cycle is an interesting and complicated subject: https://en.wikipedia.org/wiki/Carbon_cycle

TLDR is that a large part of the carbon we dump into the atmosphere is only removed by geological processes that take hundreds or thousands of years.

Re: Greenland ice sheet is close to a melting point of no return

#188

Earlier quoted context omitted.

From the same page: Previous research identified global warming of between 1 degree to 3 degrees Celsius (1.8 to 5.4 degrees Fahrenheit) as the threshold beyond which the Greenland Ice Sheet will melt irreversibly. We're already at 1.2c above pre-industrial levels. Although it will take a long period of exposure to warm air for the ice to melt, we've already been doing that for a long time. It doesn't seem reasonable…

Only 1.2? Definitely feels like much more.

Imagine how 3° will feel. 1.2 is averaged over the whole globe. Over land the difference is larger and there are strong regional variations.

Re: Greenland ice sheet is close to a melting point of no return

#189

The mass of the Greenland ice sheet is about 2.5 E15 tonnes. The average melt rate between 2003 and 2016 was about 2.5 E11 tonnes/year. At this rate it would take 10,000 years to melt completely. But the melt rate is increasing with increasing average temperatures. Wikipedia quotes a melt of 5 E 11 tonnes in 2019. Perhaps the doubling time is about 10 years? At that rate it'd take about 5,000 years to melt away. Five…

I don't think a simple exponential function is an adequate way of modelling this.

Re: Greenland ice sheet is close to a melting point of no return

#190
post #9
post #2

Ah well, here we go. I guess it's what we deserve for sitting on our hands for fifty years. So long and thanks for all the fish.

For reference, high tide where I am is ~20ft. Winter storms bring it up another 20. This will definitely require moving inland, but definitely not a “thanks for all the fish” scenario.

The greenland ice sheet is but one of the tipping points. The real problem of course will not come from warming or sea level rise per se, but from hundreds of millions of people whose homeland becomes uninhabitable for some reason or other. Some of those people have nuclear weapons.
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