Greenland’s ice: A trip back in time to see the future of climate change
There are clues to the future and past trapped in Greenland's ice.
JON GERTNER: It's hard for us here to imagine what the Greenland ice sheet is like. This is thousands of miles from the United States, as well as from Europe. It's a country that few people ever visit; it's a flyover -- maybe when you're going to Northern Europe you see this vast ice sheet. And Greenland's ice sheet, you might just imagine kind of a cupcake where the icing doesn't quite go to the edges. I mean, not only is Greenland the world's largest island, but this ice sheet, which is about 1,500 miles long and 700 miles across, covers well over 80% of the island. So there's really only this narrow strip of land around the edges that have been hospitable to settlements. Because nothing really lives on the ice sheet. This is a place where frozen temperatures get down as low as minus 80 degrees fahrenheit. It's a place that was considered forsaken by the native Inuit, a place that was somewhere you would stay away from, where evil spirits dwelled.
And it was also a place that in its center -- if you consider this kind of icing on the cupcake, in the center it's 10,000 feet high. So it's this kind of giant dome of ice, and it's two miles thick. One scientist I spent a lot of time with in Greenland called it the world's largest laboratory. Which is a kind of strange phrase when you think of it as the world's largest island, and it's covered in ice. Well, why is that? But if you look back in the history it sort of offered this opportunity for the study of the one remaining ice sheet in the northern hemisphere; the other is down south in Antarctica. But it also offered some of those early scientists a way to look back in time. Because ice, in the words of a lot of scientists, is depositional. It creates a kind of record of all the deposits that fell on it through snow. And we think, OK, well it has old snow. But it's more than that. It actually holds ancient gases. It contains records from ancient volcanic eruptions. And the way we began to access that information, because it really is information, was to drill into the ice.
And the first people to do this in a significant way, they weren't actually drilling into the ice. There was this guy Ernst Sorge, who was stationed with Alfred Wegener's team in the center of the ice sheet in 1930. And he began, literally, he was camped out under the ice with another guy -- two other guys, actually -- and he began to literally dig down with a shovel. He dug a staircase into the ice. He dug about 50 meters -- 50 feet, excuse me, down into the ice. And he began to carve out blocks and bring them back up to where they were sleeping, and he would measure them on a scale. And he wanted to measure their density. And what he discerned was that there was a very kind of discernible variation between wintertime-density snow and summertime. And he could, by doing this, sort figure out exactly how many years back in time he was going. So that was the big first step. OK, you can actually measure these sort of stripes in the ice, if you think of it that way, by kind of going down deep. And after that it became much more ambitious.
In the 1950s and 1960s scientists really brought drilling rigs up there. They tried to figure out how you could kind of drill down and pull up a core, which might sound easier than you think, but it's actually quite hard because you want to retain the pristine nature of the ice. Because what you really want to do is all sorts of experiments on chemical analysis to try and understand the isotopes in the ice. And these are kind of keys to understand what ancient temperatures are like. There are also these ancient bubbles trapped in ice, and they're keys to ancient atmospheres, too. So the farther down you go, the farther back in time you go.
And we could say, well, OK, so big deal. You can figure out maybe what the temperatures were like 1,000 years ago. But that's not a trivial piece of information. Because it's not just telling us what temperatures are like, it's telling us maybe what changed. It explains pieces of history that we might not understand. It could explain, for instance, why the Greenland Norse who came to Greenland 1,000 years ago and then mysteriously died out, why did they go? Was there a dramatic temperature change? It could explain, for instance, what happened to the Earth about 11,000 or 12,000 years ago, when we see these dramatic shifts in temperature that happened really in the space of 10 or 15 years that make us ask now, gee. We always think of climate as changing sort of gradually and slowly, but actually history, as we figured out from these ice cores, shows us that climate can actually change pretty quickly, and the Earth doesn't really care about changing slowly. Sometimes it has different modes that it can just rapidly switch into.
So there's all sorts of information that we've found out from the center of Greenland's ice. It's kind of a key to the past. Sometimes it's not always reassuring, but it's always given us new knowledge that helps us think, again, about this place as a big laboratory, and not just a big hunk of ice.
- The Greenland ice sheet covers 80% of the island of Greenland. The sheet is 1,500 miles long, 700 miles across, and two miles thick. Scientists call it the largest laboratory in the world.
- By studying the minerals and gasses trapped in layers of ice, glaciologists can unravel mysteries of the past, such as what the temperature was 1,000 years ago, or search for clues as to why the Greenland Norse people vanished.
- Ice cores are a key to the past that also unlocks the future. Studying Greenland's ice sheet is yielding valuable information about the future of climate change.
- How NASA's ICESat-2 will track ice changes in Antarctica, Greenland ›
- Greenland loses 4 trillion pounds of ice in one day - Big Think ›
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Water may be far more abundant on the lunar surface than previously thought.
- Scientists have long thought that water exists on the lunar surface, but it wasn't until 2018 that ice was first discovered on the moon.
- A study published Monday used NASA's Stratospheric Observatory for Infrared Astronomy to confirm the presence of molecular water..
- A second study suggests that shadowy regions on the lunar surface may also contain more ice than previously thought.
Credits: NASA/Daniel Rutter<p>Still, it's not as if the moon is dripping wet. The observations suggest that a cubic meter of the lunar surface (in the Clavius crater site, at least) contains water in concentrations of 100 to 412 parts per million. That's roughly equivalent to a 12-ounce bottle of water. In comparison, the same plot of land in the Sahara desert contains about 100 times more water.</p><p>But a second study suggests other parts of the lunar surface also contain water — and potentially lots of it. Also publishing their findings in <a href="https://www.nature.com/articles/s41550-020-1198-9#_blank" target="_blank">Nature Astronomy</a> on Monday, the researchers used the Lunar Reconnaissance Orbiter to study "cold traps" near the moon's polar regions. These areas of the lunar surface are permanently covered in shadows. In fact, about 0.15 percent of the lunar surface is permanently shadowed, and it's here that water could remain frozen for millions of years.</p><p>Some of these permanently shadowed regions are huge, extending more than a kilometer wide. But others span just 1 cm. These smaller "micro cold traps" are much more abundant than previously thought, and they're spread out across more regions of the lunar surface, according to the new research.</p>
Credit: dottedyeti via AdobeStock<p>Still, the second study didn't confirm that ice is embedded in micro cold traps. But if there is, it would mean that water would be much more accessible to astronauts, considering they wouldn't have to travel into deep, shadowy craters to extract water.</p><p>Greater accessibility to water would not only make it easier for astronauts to get drinking water, but could also enable them to generate rocket fuel and power.</p><p style="margin-left: 20px;">"Water is a valuable resource, for both scientific purposes and for use by our explorers," said Jacob Bleacher, chief exploration scientist in the advanced exploration systems division for NASA's Human Exploration and Operations Mission Directorate, in a statement. "If we can use the resources at the Moon, then we can carry less water and more equipment to help enable new scientific discoveries."</p>
A study finds 1.8 billion trees and shrubs in the Sahara desert.
- AI analysis of satellite images sees trees and shrubs where human eyes can't.
- At the western edge of the Sahara is more significant vegetation than previously suspected.
- Machine learning trained to recognize trees completed the detailed study in hours.
Why this matters<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU2MDQ1OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzOTkyODg5NX0.O3S2DRTyAxh-JZqxGKj9KkC6ndZAloEh4hKhpcyeFDQ/img.jpg?width=980" id="3770d" class="rm-shortcode" data-rm-shortcode-id="3c27b79d4c0600fb6ebb82e650cabec0" data-rm-shortcode-name="rebelmouse-image" />
Area in which trees were located
Credit: University of Copenhagen<p>As important as trees are in fighting climate change, scientists need to know what trees there are, and where, and the study's finding represents a significant addition to the global tree inventory.</p><p>The vegetation Brandt and his colleagues have identified is in the Western Sahara, a region of about 1.3 million square kilometers that includes the desert, <a href="https://en.wikipedia.org/wiki/Sahel" target="_blank">the Sahel</a>, and the <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/subhumid-zones" target="_blank" rel="noopener noreferrer">sub-humid zones</a> of West Africa.</p><p>These trees and shrubs have been left out of previous tabulations of carbon-processing worldwide forests. Says Brandt, "Trees outside of forested areas are usually not included in climate models, and we know very little about their carbon stocks. They are basically a white spot on maps and an unknown component in the global carbon cycle."</p><p>In addition to being valuable climate-change information, the research can help facilitate strategic development of the region in which the vegetation grows due to a greater understanding of local ecosystems.</p>
Trained for trees<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU2MDQ3MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNTk5NTI3NH0.fR-n1I2DHBIRPLvXv4g0PVM8ciZwSLWorBUUw2wc-Vk/img.jpg?width=980" id="e02c0" class="rm-shortcode" data-rm-shortcode-id="79955b13661dca8b6e19007935129af1" data-rm-shortcode-name="rebelmouse-image" />
Credit: Martin Brandt/University of Copenhagen<p>There's been an assumption that there's hardly enough vegetation outside of forested areas to be worth counting in areas such as this one. As a result the study represents the first time a significant number of trees — likely in the hundreds of millions when shrubs are subtracted from the overall figure — have been catalogued in the drylands region.</p><p>Members of the university's Department of Computer Science trained a machine-learning module to recognize trees by feeding it thousands of pictures of them. This training left the AI be capable of spotting trees in the tiny details of satellite images supplied by NASA. The task took the AI just hours — it would take a human years to perform an equivalent analysis.</p><p>"This technology has enormous potential when it comes to documenting changes on a global scale and ultimately, in contributing towards global climate goals," says co-author Christian Igel. "It is a motivation for us to develop this type of beneficial artificial intelligence."</p><p>"Indeed," says Brandt says, "I think it marks the beginning of a new scientific era."</p>
Looking ahead and beyond<p>The researchers hope to further refine their AI to provide a more detailed accounting of the trees it identifies in satellite photos.</p><p>The study's senior author, Rasmus Fensholt, says, "we are also interested in using satellites to determine tree species, as tree types are significant in relation to their value to local populations who use wood resources as part of their livelihoods. Trees and their fruit are consumed by both livestock and humans, and when preserved in the fields, trees have a positive effect on crop yields because they improve the balance of water and nutrients."</p><p>Ahead is an expansion of the team's tree hunt to a larger area of Africa, with the long-term goal being the creation of a more comprehensive and accurate global database of trees that grow beyond the boundaries of forests.</p>
Tea and coffee have known health benefits, but now we know they can work together.
Credit: NIKOLAY OSMACHKO from Pexels
- A new study finds drinking large amounts of coffee and tea lowers the risk of death in some adults by nearly two thirds.
- This is the first study to suggest the known benefits of these drinks are additive.
- The findings are great, but only directly apply to certain people.