ice sheets

Climate change and Antarctic meteorites

May 1, 2024 By EarthWise Leave a Comment

Researchers from Switzerland and Belgium have investigated the effects of the warming climate on access to meteorites in Antarctica. Meteorites are of great scientific interest because they provide unique information about the makeup of our solar system. Of all the meteorites that people have found, 62.6% of them were found in Antarctica.

Why is this? It is not because more meteorites land in Antarctica. Statistically, they can land anywhere on earth. Most end up in the ocean since the world’s oceans cover 70% of the planet.

Meteorites in Antarctica are more visible because environmental conditions are favorable for their preservation and their visibility. The arid and cold Antarctic environment helps to preserve meteorites and the lack of rocks and contrast with ice makes spotting meteorites much easier. The flow of ice sheets tends to concentrate meteorites in so-called meteorite stranding zones where the dark colored space rocks can be easily detected.

There are an estimated 300,000 to 800,000 meteorites in Antarctica. When meteorites warm up, they can transfer heat to the ice, which locally melts. Eventually, the meteorites sink beneath the surface. A recent study using satellite imagery, climate model projections, and AI predicts that for every tenth of a degree of increase in global air temperature, an average of 9,000 meteorites in Antarctica will disappear from the surface and will no longer be able to be found.

The study estimates that a quarter of Antarctic meteorites will be lost to glacial melt by 2050. If warming continues to accelerate, closer to three-quarters of the meteorites on the continent will be lost.

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Climate change threatens Antarctic meteorites

Photo, posted April 21, 2005, courtesy of Kevin Walsh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Positive tipping points and climate

January 29, 2024 By EarthWise Leave a Comment

We often hear about tipping points and climate change. Tipping points are critical thresholds that, when crossed, lead to large, accelerating, and often irreversible changes. Some of the ones of concern with the climate are thawing permafrost, melting glaciers and ice sheets, and global temperatures reaching certain levels. These are all tipping points that are essential to avoid.

A study published in the journal One Earth by researchers at the University of Exeter in the UK contends that in order to avoid the severe consequences of climate change, we need to trigger some positive tipping points.

Many climate-friendly changes are happening too slowly. Triggering positive tipping points is a way to rapidly reach the high levels of decarbonization required to avoid triggering the negative tipping points of great concern.

Reaching a positive tipping point is a way that beneficial changes can rapidly gain momentum. One example is the adoption of electric vehicles. It has clearly reached a tipping point across Scandinavia and has happened rapidly. Norway has managed to transition the market share of electric vehicles from under 10% to nearly 90% in less than 10 years. At some point, everybody wanted an electric car. This is evidence that positive tipping points can happen.

Many of the other forms of decarbonization need to move from their current level of adoption to rapid expansion. A combination of affordability, attractiveness, availability, and political will are needed to trigger tipping points. Exactly what those tipping point are is not necessarily known, but unless something accelerates the current pace of change, it will be very difficult to prevent negative climate tipping points from changing the world in destructive ways.

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Positive tipping points must be triggered to solve climate crisis

Photo, posted July 8, 2023, courtesy of Michael Swan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Polar Ice Melting | Earth Wise

May 30, 2023 By EarthWise Leave a Comment

Sea levels are rising and ocean warming is responsible for the bulk of that rise. As water heats up, it expands, which drives up sea levels. But on top of that, global warming is melting the polar ice sheets, and that is leading to about a quarter of the world’s sea level rise. So far, polar melting has fueled about an inch of sea level rise, two-thirds from Greenland and one third from Antarctica. According to scientists, by the end of this century, melting polar ice caps could raise sea levels between 6 and 10 inches.

The seven worst years for polar ice sheet melting have occurred during the past decade. The worst year on record was 2019. The loss in 2019 was driven by an Arctic summer heatwave, which resulted in record melting from Greenland, amounting to nearly 500 billion tons melted that year. Antarctica lost 180 billion tons of ice that year, mostly due to melting glaciers and record melting from the Antarctic Peninsula.

Ice losses from Greenland and Antarctica can now be reliably measured by satellites in space. A team of researchers led by Northumbria University in the UK has combined 50 satellite surveys taken between 1992 and 2020.

They have found that the Earth’s polar ice sheets have lost over 8,000 billion tons of ice over that time period. That much ice corresponds to an ice cube roughly 12 miles high.

The satellite technology is now at the stage where the ice sheet status can be continuously updated. Such monitoring is critical to predict the future behavior of the ice sheets and provide risk warnings of the dangers that coastal communities around the world will face.

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Polar ice sheet melting records have toppled during the past decade

Photo, posted December 19, 2017, courtesy of Jasmine Nears via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global Flood Risk From Melting Ice | Earth Wise

December 13, 2021 By EarthWise Leave a Comment

Approximately 10% of the land area on Earth is covered by ice. This includes glaciers, ice caps, and the ice sheets of Antarctica and Greenland. Nearly 70% of all fresh water on earth is locked away in ice. If all this land ice were to melt, global sea levels would rise by more than 200 feet.

According to new research led by researchers at the University of Leeds in the U.K., global warming is causing extreme ice melting events in Greenland to become more frequent and more intense over the past 40 years, leading to an increased risk of flooding worldwide.

According to the findings, which were recently published in the journal Nature Communications, approximately 3.85 trillion tons of ice has melted from the surface of Greenland and into the ocean during the past decade alone. That’s enough melted ice to cover all of New York City with nearly 15,000 feet of water.

Rising sea levels threaten the lives and livelihoods of those living in coastal communities around the world. Beyond the obvious risk of flooding in low-lying areas, rising seas also disrupt marine ecosystems that many coastal communities rely on for food and work.

Rising sea levels can also alter patterns of ocean and atmospheric circulation, which in turn affect weather conditions around the planet.

Estimates from models suggest that melting ice from Greenland will contribute between 1 inch and 9 inches to global sea level rise by 2100.

These findings are just another reminder of how we need to act urgently to mitigate climate change if we want to prevent the worst-case scenarios from becoming reality.

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Increased frequency of extreme ice melting in Greenland raises global flood risk

Photo, posted April 21, 2017, courtesy of Markus Trienke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Accelerating Global Glacier Loss | Earth Wise

June 10, 2021 By EarthWise Leave a Comment

Glaciers represent the snows of centuries compressed over time to form flowing rivers of ice. Glaciers always change, accumulating snow in the winter and losing ice to melting in the summer. But in recent times, the melting has been outpacing the accumulation.

Glaciers are a sensitive indicator of climate change. They have been melting at a high rate since the mid-20th century – regardless of altitude or latitude. But up until recently, the full extent of glacial ice loss has only been partially measured and understood.

Now, according to new research led by scientists from ETH Zurich in Switzerland and the University of Toulouse in France, nearly all the world’s glaciers are becoming thinner and losing mass. And the changes are accelerating. The study, which is the most comprehensive and accurate of its kind to date, is the first to include all the world’s glaciers – around 220,000 in total – excluding the Greenland and Antarctic ice sheets. The research team’s findings were recently published in the journal Nature.

Between 2000 and 2019, the world’s glaciers lost an average of more than 294 billion tons of ice per year. Between 2000 and 2004, glaciers lost an average of about 250 billion tons of ice each year. But between 2015 and 2019, ice mass loss jumped up to an average of approximately 328 billion tons annually.

Glacial melt is responsible for 21% of the observed sea level rise during this two decade time period studied.

This research is just another reminder of how we need to act urgently if we want to prevent the worst-case climate change scenario from becoming a reality.

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Global glacier retreat has accelerated

Photo, posted September 17, 2015, courtesy of Richard Whitaker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rising Seas And Wastewater Leakage | Earth Wise

April 28, 2021 By EarthWise Leave a Comment

Global mean sea level has risen nearly 9 inches since 1880, with over two inches of that over just the last 25 years. The rising water level is primarily due to two factors: additional water in the oceans coming from melting glaciers and ice sheets; and the thermal expansion of seawater as it warms. Climate models estimate that over the course of the century, global sea levels will rise at least a foot even if efforts to reduce greenhouse gas emissions are quite successful and, in the worst case, levels could rise as much as 8 feet.

Faced with this situation, the greatest concerns are, initially, increasing amounts of coastal flooding and erosion and, as things get worse, inundation of coastal regions making many places uninhabitable and creating millions of climate refugees.

Recently, computer modeling studies have focused on an additional imminent problem: the flooding of coastal wastewater infrastructure, which includes sewer lines and cesspools.

A new study by the University of Hawaii at Manoa is the first to provide direct evidence that tidally driven groundwater inundation of wastewater infrastructure is already occurring in urban Honolulu. The study shows that higher ocean water levels are leading to wastewater entering storm drains and the coastal ocean. The result is degradation of coastal water quality and ecological health.

The researchers used chemical tracers to detect groundwater discharge and wastewater present at multiple low-lying areas during spring tides. During high tides, storm drains become channels for untreated wastewater to flood streets and sidewalks.

People tend to think of sea-level rise as a future problem, but there are already serious effects going on today that are only going to get worse.

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Sea-level rise drives wastewater leakage to coastal waters

Photo, posted August 23, 2011, courtesy of Eric Tessmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Caspian Sea And Climate Change | Earth Wise

January 22, 2021 By EarthWise Leave a Comment

According to the National Oceanic and Atmospheric Administration, global sea levels have been rising over the past century, and the rate has increased in recent decades. Sea levels are currently rising about one-eighth of an inch every year.

Sea level rise is caused primarily by two factors related to climate change: the added water from melting glaciers and ice sheets, and the expansion of seawater as it warms. While climate change is causing global sea levels to rise, higher temperatures in other regions are having exactly the opposite effect. The water levels are falling.

According to researchers from the University of Bremen in Germany, the Caspian Sea is a perfect example of how a body of water will change. While it is named a sea due to its size and high salinity, the Caspian Sea is actually a lake. In fact, it’s the largest lake in the world. Its largest inflow is the Volga River and it has no natural connection to the ocean. Its water level is determined by the proportional influences of inflow, precipitation, and evaporation. Climate change is causing increased evaporation, which leads to a declining water level.

According to the research team, the water level of the Caspian Sea could fall by 29 to 59 feet during this century.

The Caspian Sea is surrounded by Kazakhstan, Turkmenistan, Iran, Azerbaijan and Russia. It’s an important regional water reservoir, and a biological and commercial center.

The researchers hope the Caspian Sea will be used as an example in scientific research to assess the vulnerability of other regions to falling water levels.

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Climate crisis is causing lakes to shrink

Photo, posted October 31, 2016, courtesy of Amanderson2 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Rising Threat Of Rising Seas | Earth Wise

February 3, 2020 By EarthWise Leave a Comment

Global sea level rose by about 6 inches during the 20th century. It is currently rising more than twice as fast and accelerating. The rate of rise was 2.5 times faster from 2006 to 2016 than it was for nearly all of the 20th century.

Sea level rise occurs when glaciers and ice sheets lose mass. Much of that meltwater comes from Greenland and Antarctica. But levels also rise because, as water warms, it expands. Added to that are the effects of human activities such as groundwater depletion and a geological phenomenon called isostatic adjustment that is going on in parts of the East Coast where the land is actually sinking.

In Atlantic Canada, sea level rise is outpacing the global average and has already led to boardwalks swamped by swelling tides, drowned forests, submerged wharfs, and threatened historic shoreline buildings.

Recent research suggests that globally, land now occupied by 300 million people could be affected by floods at least once a year by 2050 unless carbon emissions are significantly reduced, and coastal defenses strengthened. (This new figure is more than three times higher than earlier estimates).

Researchers at Dalhousie University in Nova Scotia are studying nature-based strategies for mitigating the effects of the rising seas. These include conserving or restoring coastal ecosystems like dunes, wetlands, and reefs which could provide protection at a lower cost than building seawalls and other man-made obstacles. Wetlands, for example, can reduce the force of waves and act as obstacles to storm surges, while also trapping sediment and stemming erosion. Wetlands also serve as important carbon stores, but it is estimated that roughly half of the world’s coastal wetlands have been lost over the past 100 years to human activity and extreme weather events.

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The Looming Threat of Rising Sea Levels – And What We Can Do About it

Photo, posted February 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Antarctic Warming

April 23, 2019 By EarthWise Leave a Comment

East Antarctica is the coldest place on Earth. It makes up two-thirds of the continent, is home to the South Pole, and has vast ice sheets that have been around for tens of millions of years and are nearly three miles thick in places. Temperatures there hover around 67 degrees below zero. In 2010, a few spots on East Antarctica’s polar plateau reached a record-breaking 144 degrees below zero.

But almost unbelievably, parts of the East Antarctic seem to be melting.

Scientists are seeing worrying signs of ice loss in the East Antarctic. Glaciers are starting to move more quickly and are dumping their ice into the Southern Ocean. Satellite images show the fast-moving ice. The biggest glacier – the Totten Glacier – alone contains enough ice to raise global sea levels by over 12 feet.

The Antarctic as a whole contains about 90% of the planet’s ice. In theory, if it all melted, it would raise global sea levels by an average of 200 feet.

The growing concerns about eastern Antarctica are not that its interior plateau will soon start to melt. It is still extremely cold there and should stay that way for a long time. But its edges, which are in contact with warming ocean waters, are the real worry. As the region’s ice shelves, which float atop the Southern Ocean, erode, the vast glaciers behind them could rapidly accelerate their slide into the sea.

Today, satellites show huge glaciers moving rapidly toward the coast, with wide rivers of ice sometimes moving several miles a year. In the face of rapid change and limited data, it is difficult to predict what the Antarctic will do in the future. But it doesn’t look good.

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Polar Warning: Even Antarctica’s Coldest Region Is Starting to Melt

Photo, posted January 3, 2013, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Glacial Engineering

October 24, 2018 By EarthWise Leave a Comment

As the world struggles with trying to limit carbon emissions and slow the pace of global warming, there is increasing analysis of various forms of geoengineering. Often, these consist of nearly unthinkable efforts to intervene in the climate on a global scale with unpredictable and possibly catastrophic consequences.

[Read more…] about Glacial Engineering

Increasing Antarctic Ice Loss

July 31, 2018 By EarthWise Leave a Comment

Antarctica’s ice sheets contain enough frozen water to raise sea levels globally about 190 feet. Ice in the Antarctic is melting at a record-breaking rate and subsequent sea rises could have catastrophic consequences around the world. So, it is no surprise that scientists have been closely tracking ice loss in recent decades to understand both the current and future impacts of climate change.