Geoengineer polar glaciers to slow sea-level rise | Hacker News Reader

Geoengineer polar glaciers to slow sea-level rise

nature.com

56 pointsehudla45 comments

This is one of these interesting topics where people are very likely to ask, "Have they thought of this?" And it would be great if there were a list of discarded ideas along with the reasons for why they were discarded.

For instance I specifically would like to know if large areas of IR reflective material could be used to cover strategic areas in the arctic and antarctic to build up ice barriers. Coat sensitive areas with something that stops the ice from absorbing heat and hey presto maybe you get significant gains for your investment?

Some people are actually working on that. For example, Ice911 is testing high-albedo sand: http://www.ice911.org/

Arctic researcher Peter Wadhams has been advocating geoengineering. His recent book A Farewell to Ice is a grim but fascinating read. Here's a short piece he wrote for Scientific American: https://www.scientificamerican.com/article/geoengineering-la...

Other proposals for increasing arctic albedo include using wind-powered ships to seed low-altitude clouds with seawater, injecting sulfur dioxide to high altitudes, and actually making more ice by using millions of windmill buoys to pump cold deep water to the surface. Here's an article on that last one: https://asunow.asu.edu/20161222-solutions-asu-scientists-pro...

Of course, ice is already very high albedo. Might be difficult to find something better that you can directly apply to the ice.

One idea for helping to terraform Mars (by thickening the atmosphere) is to apply black carbon dust to the glaciers. We're kind of doing that by accident here by burning fossil fuels that produce soot that ends up on glaciers. So reducing fossil fuel burning and soot production would help do what you're trying to do.

Geoengineering is just a money sink if the root cause isn't tackled. This proposal might slow down SLR, but the oceans will continue to sour, temperatures to rise and weather becomes more economically threatening.

> Geoengineering is just a money sink if the root cause isn't tackled.

Sounds like the perfect industry for the consumer-age in that case.

Indeed, but don't underestimate the value of buying time, especially when it's measured in centuries. That gives us time to transition our economies away from fossil fuels, time to develop more efficient agriculture and industry, perhaps even the holy grail of clean energy - fusion power.

In theory it also buys us time to migrate more slowly away from the coast, or deploy carbon sequestration technologies, or build sea walls. All of which may get easier with more advanced technology. But I don't have much faith in humans doing that if we move the consequences further out into the future. We're so collectively short-sighted as a species.

What is the exact sea-level that is perfect and should be maintained --or returned to-- by all means?

I have a similar question about the perfect amount of atmospheric CO2. We do know that the long-term trend of CO2 was headed down to a dangerously low level (plants would starve and land-based plant life would have catastrophically ended by 150ppm).

275 million people live in cities that will be flooded if we have a 3C warming. That is a pretty nice reason to maintain that sea level. https://www.theguardian.com/cities/ng-interactive/2017/nov/0...

So the current sea level is the one that must be kept? forever? or should it rather be the level at the start of British Industrialization, let's say in 1760?

What about sea level changes that are not caused by us? should we stop that, too? in either direction? forever?

> So the current sea level is the one that must be kept?

For now, yes. There are millions of people who will be impacted if we don't.

If there is a reason to maintain a different sea level, we can weigh it against the impact of those currently affected.

The people in 1760 are long dead, their oceans and their levels are less relevant.

Thanks, that makes sense as a goal, to evaluate and minimize impact on current coastal populations. I assume future coastal population centers would actively shift inland, over multiple decades, if they take into account predicted sea level changes over the next 200 to 2,000 years.

In a capitalist society, I wouldn't expect that. What would be the market incentive to migrate? As it stands currently, coastal property is the most valuable. There would need to be a mechanism to drive that migration.

Perhaps a system that adds the cost of maintaining the current sea level to owning beachfront property?

Market insurance without government support, and absence of emergency funding after disasters...

We are still in an ice age and we just happen to live in an interglacial period. The Earth has the large polar continent, and multiple other continents arranged such that they greatly impede the free flow of water currents around the globe that are necessary for mass glaciation. In these conditions, glaciation can easily lead to a positive feedback loop and once that gets going the effect is rapid (think order months to years, not decades).

Isn't sea level rise mostly caused by thermal volumetric expansion not ice melting?

I’m increasingly of the opinion that slow is not the way to go. Too many people refuse the existence of human caused climate change. So let them feel the brutal, undeniable affects. Maybe we’ll luck out and we’ll pull our collective hands off the hot iron before permanent scarring occurs.

That isn't how this works.

The people who believe climate change the least are those that typically live in the middle of America i.e. the least to be directly affected. I assure you that when you speak to Pacific Islanders from Cook Islands, Fiji etc they very much believe climate change is real and are desperate for action to be taken.

If you really want things to change help change the politicians in the US. Because China is doubling down on solutions and we really need the US to be doing the same.

I’m doing everything I can. But the current US political atmosphere is depressing.

Edit-People in that middle America that you speak of seem to have forgotten the entire Cold War and welcomed Russia as allies! I mean, the Cold War didn’t ever end!

> Because China is doubling down on solutions and we really need the US to be doing the same.

I hadn't heard this. can you give some examples, please?

There's about a thirty-year delay, just like turning up a burner on the stove takes a while to heat the water. By the time people feel it that much, it'll be far too late.

We have to put on the brakes before we get irreversible feedback effects, where natural systems start emitting enough greenhouse gases that it doesn't matter anymore what we do.

Not sure what data you are basing this on. I tend to think we are heading into a cooling period.

They're both basic climate physics, and not related to short-term fluctuations.

Further, your example was an analogy.

When you add energy input to a system, it doesn't immediately reach its new equilibrium temperature. That's not an analogy, it's another example of the same physical process.

> it's another example of the same physical process

That's an analogy.

Then all of experimental physics is based on analogies.

When a comparison between phenomena is made for the purpose of explanation, yes, analogy is commonly used in the teaching of physics.

But it is better to say that experimental physics is based on the collection of data about a particular phenomenon, and fitting those data to mathematical models to test how well their predictions hold. And that is not analogy.

In an experiment you try out a simple system to see how it works. Then you use those same physical principles to figure out how a more complex system works. An example would be heating water on a stove to see how fluids respond to energy input.

> And that is not analogy.

technically analogy has a broad definition that applies anytime you compare two things.

We possibly would have, if we weren't warming the climate through human activity.

> I would say it is significant that temperatures of the most recent decade exceed the warmest temperatures of our reconstruction by 0.5 degrees Fahrenheit, having few -- if any -- precedents over the last 11,000 years. Additionally, we learned that the climate fluctuates naturally over the last 11,000 years and would have led to cooling today in the absence of human activity.

https://www.theguardian.com/environment/climate-consensus-97...

Current temperature is maybe the hottest in recorded history (which is about 150 years) and that is a big maybe. Its definitely not the hottest in human history. Medieval warming period was much warmer than it is now. I would even argue the 1930s were hotter as well.

> Current temperature is maybe the hottest in recorded history (which is about 150 years)

“Recorded history” is a period much longer than 150 years.

> Medieval warming period was much warmer than it is now.

No, it wasn't. Global aversge temperature is above the peak of anything that might be in the MWP today (the MWP had a really small global effect, with different local warming periods in different regions.)

> I would even argue the 1930s were hotter as well.

Well, you can argue anything, but finding data to support that argument might be difficult.

Until about the mid-90s of last century the Medieval Warm Period was for climate researchers an undisputed fact. The IPCC itself reported this as such in their 1990 report and included this graph.

https://i1.wp.com/www.science-skeptical.de/wp-content/upload...

Here is another chart published by IPCC in 1995 it shows both the Medieval warm period and the 1930s as being hotter than it is now.

https://stevengoddard.files.wordpress.com/2011/05/screenhunt...

Since then there has been an effort to erase this data from the record because it contradicts current climate change narrative. None of what Im saying is a theory. These are facts and there are loads of leaked emails and testimony under oath that says as much.

https://www.youtube.com/watch?v=u1rj00BoItw

Up your research game my friend.

> Until about the mid-90s of last century the Medieval Warm Period was for climate researchers an undisputed fact.

The MWP is, if not undisputed, a widely accepted fact, though of dubious significance; a very slight rise in average global temperatures over a several centuries long period does show up, as, within that long period, do shorter and much more pronounced and non-synchronized regional warm periods.

Global average temperatures in the MWP, though, were notably lower than today.

> The IPCC itself reported this as such in their 1990 report and included this graph.

Maybe, maybe not. Given your misrepresentation on the next one, I'm not taking your word for it, and in any case there is no clear indication of what that is a graph of; it looks a lot like the graph of European temperatures provided in your other link, but with lower resolution and presumably an earlier end date, which of course is immaterial to the discussion of global temperature trends.

> Here is another chart published by IPCC in 1995 it shows both the Medieval warm period and the 1930s as being hotter than it is now.

Nope, that's a chart published by someone else later that claims to be based on a diagram published by the IPCC which (obviously) doesn't show temperatures today at all (1995 is more than two decades ago, and global warming didn't stop then), and, in any case, doesn't show global temperature at all, either, only European temperature. Regional temperature trends don't always reflect global trends. Yes, Europe experienced notable local warming in the MWP and the early 20th century (and dramatic local cooling in the period sometimes called the “Little Ice Age” which, IIRC, doesn't show up at all in global trends and is at least in part within the global MWP, though the warm regions that brought up the global aversge at the time were elsewhere.)

> Since then there has been an effort to erase this data from the record

No, the local trends that the charts you point to reflect are widely acknowledged by climate scientists today—they are, however, local, not global.

> Up your research game my friend

Hey, I'm not the one who offered a chart without reading the caption. Having a good research game is more than just spamming links without understanding the content.

Has there been any documented rise yet or is it supposed to start later?

There was a huge rise around 12,800-11,600 years ago after the last ice age came to an abrupt end. As far as I'm aware ocean levels have been mostly stable ever since.

Formally, the current ice age hasn't ended and its effects will return in full force; we happen to live in an interglacial period, still overall a colder climate than when the Earth has not been in an Ice Age.

You might be right. I'm talking specifically about the 26k year cycle due to earths wobble.

Measurements have been averaging a little above 3mm per year for the last two decades[0]. This is believed to be about double the post-Ice-Age background rate of a century ago, and it is predicted to accelerate further (though it has yet to do so noticeably).

[0]http://sealevel.colorado.edu/

In fact, that same graph used to have a trend line of 3.2 mm/yr, and is now 3.1. I've been checking in with that site off-and-on for the last few years. At the current linear rate, we're looking at an increase of 0.25m by 2100. To get to the 1m by 2100 that is predicted, we would have to have a linear sea level rise of 12.4 mm/yr.

The graph displayed shows some variable years a few years ago, but it's mostly been pretty linear. The graph shows 20 years or so of data, and we're 82 years out from 2100. I would expect to see it curving up sometime soon, but it hasn't done that yet.

I would expect SLR to be highly nonlinear.

There is a nice interactive graph of the Jason series satellite data at: https://www.aviso.altimetry.fr/en/data/products/ocean-indica...

You can see the acceleration by shifting the time sliders to choose different years.

1 meter in 100 years sounds a bit anti-climactic. With the kind of socioeconomic problems rising it sounds kind of dumb thing to care about. People will have decades to move and evacuate. Sure, some infrastructure will be wasted, but it's not like the end of the world that everyone is trying to portray.

Even small changes can have pretty big consequences ... for example, some hypothesize that climate change may have had a role in the "Arab Spring" that started a chain of events that's still unfolding in the middle east: https://www.americanprogress.org/issues/security/reports/201...

"“The Arab Spring and Climate Change” does not argue that climate change caused the revolutions that have shaken the Arab world over the past two years. But the essays collected in this slim volume make a compelling case that the consequences of climate change are stressors that can ignite a volatile mix of underlying causes that erupt into revolution."

TL;DR climate change contributed to changing agricultural conditions, which led to increased migration from rural to urban centers, which was a "stressor" that probably contributed to an already volatile situation ... the proverbial straw that broke the camel's back (pun not necessarily intended).

So yeah, a meter of water level rise would change a massive amount of coastlines ... which would result in population shifts, which would result in economic activity changing, which could result in ... we'll see.

Of the many things might have caused the revolution, global warming wasn't one of them. Egypt is at a country's developmental phase when urbanization happens. Also it takes a lot of confidence to attribute 2 years of dryness to climate change. I'm trying to keep my composure but this is a laughable statement.

Here's a neat little tool I found: http://flood.firetree.net/

I guess that by 2100 the only problems my area will run into is a couple of deltas being flooded by saltwater and a few random patches of 50m incursions, all but one uninhabited. I think I'll survive, and my children will probably be fine.

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