Climate 411

Why melting polar ice is a debt we can’t afford to carry

By Alice Alpert / Published: January 19, 2024

Near Palmer Station, Antarctica. Photo: Alice Alpert

We now know it’s official – 2023 was the warmest year ever recorded.

Citizens across the globe felt the impacts long before it was confirmed. There were unprecedented wildfires in Canada that turned the New York sky orange. Phoenix saw a record-breaking 31 consecutive days with temperatures topping 110 degrees.

Along with these very immediate impacts, we also need to pay attention to the longer-term impacts of climate change. Specifically, when it gets hotter, ice locked in glaciers and ice sheets melts and ends up as water in the ocean. It takes a long time to melt, but eventually all that water raises the level of the ocean.

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Also posted in Basic Science of Global Warming, Extreme Weather, Oceans, Science / Read 7 Responses

Four takeaways on climate change and sea level rise in the latest IPCC report

By Tianyi Sun / Published: October 3, 2019

The Intergovernmental Panel on Climate Change has published yet another alarming report about the dangers we face from the climate crisis.

The Special Report on the Ocean and Cryosphere in a Changing Climate synthesizes the latest science on how the oceans and frozen parts of the world have changed, and will continue to change, because of global warming.

More than 100 scientists from 36 countries summarized findings from almost 7,000 peer reviewed research studies. The authors addressed over 30,000 comments from expert reviewers and governments in 80 countries.

A major focus of the report is sea level rise, a climate change impact that is especially serious to those who live in coastal regions – which is more than a quarter of the world’s population. Recent advances in science, such as higher quality data, improved physical understanding, and agreements across modeling studies have improved understanding of the threat of sea level rise.

Here are four of the report’s most important takeaways on sea level rise:

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Also posted in Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, News, Oceans, Policy, Science / Read 3 Responses

A look back at 2017: The year in weather disasters – and the connection to climate change

By Casey Ivanovich / Published: January 3, 2018

Port Arthur, Texas after Hurricane Harvey. Photo: SC-HART

From hurricanes to heat waves, 2017 produced countless headlines concerning extreme weather and the devastation left in its wake.

We tend to think of extreme weather as an unpredictable, external source of destruction. When faced with catastrophes, we don’t always recognize the role we play in intensifying their impacts.

But as human-induced climate change continues to progress, extreme weather is becoming more frequent and dangerous. Without immediate greenhouse gas mitigation efforts, last year’s unprecedented disasters may soon become the norm.

Here’s a look back at the worst weather of 2017 and how these events may have been affected by climate change (and scroll down to see a timeline of the year’s worst weather).

JANUARY

  1. Massive flooding drowns California – Intense rains in January provided a much needed respite from California’s longstanding drought, but quickly tipped from satiating to inundating. Within the first 11 days of the year, California received 25 percent of the state’s average annual rainfall. Flooding and mudslides forced more than 200,000 people to evacuate their homes and caused an estimated $1.5 billion in property and infrastructure damages.

    The rapid shift from drought to flooding may be a marker of climate change. As temperatures warm, precipitation falling as rain rather than snow and expedited snow melt lead to the earlier filling of reservoirs. Such a shift increases the likelihood of both summer droughts and winter flooding, with the latter intensified by a warming atmosphere that holds more moisture and deposits greater precipitation in heavy rainfall events.

  2. Heat wave sizzles in Australia – High heat persisting overnight in the New South Wales and Southern Queensland regions of Australia induced a series of devastating heat waves throughout January and February. Following a record-setting month in which the city reached its highest ever overnight minimum temperature for December, Sydney experienced the hottest night in January since weather records began in the mid-1800s.

    Analysis has shown that these extreme summer temperatures are 10 times as likely due to the influence of climate change. With rising global temperatures, heat waves are expected to become more intense, frequent, and longer lasting. Australia was just one of many regions to experience these developing changes in 2017.

  3. Extreme heat melts the North Pole – Recent history of escalating temperatures in the Arctic could not dull the shock when temperatures near the North Pole reached more than 50 degrees Fahrenheit above regional averages this winter. The heat wave associated with this spike is not only dramatic in intensity, but frequency – heat this extreme usually occurs about once each decade, yet this event was the third recorded in just over a month.

    There exists an essential feedback between sea ice melt and Arctic warming – the more we warm, the more ice melts, lowering the region’s reflectivity of sunlight and increasing warming intensity. While these processes are usually gradual, weather variability can kick dramatic warming events into high gear. The winter heat waves experienced in the Arctic provide examples of such a combination, which may occur every few years should we reach a 2 degree Celsius global temperature rise.

FEBRUARY

  1. Drought brings risk of famine to Somalia – At a time when a staggering 6.2 million people – half of Somalia’s population – required urgent humanitarian aid, the World Health Organization released an official warning that Somalia was on the verge of famine. Such categorization would clock in as Somalia’s third famine in 25 years, the most recent of which led to the death of 260,000 people.

    After years of scarce rainfall, the nation continues to face widespread food insecurity, reduced access to clean water, and increased risk for drought-related illness. Analysis of both observational and modeling data suggests that only a small increase in the nation’s dry extremes can be attributed to climate change. However, as dry regions become progressively drier in a warming climate, similar national disasters may become increasingly common.

JUNE

  1. Extreme heat blisters the Southwestern United States – In June, an intense heat wave blazed across the Southwestern U.S. and left record high temperatures in its trail. Daily records included 127 degrees Fahrenheit in Death Valley. All-time records were reached in Las Vegas, Nevada and Needles, California at 117 degrees Fahrenheit and 125 degrees Fahrenheit, respectively. High heat triggered public health concerns and led to power outages in the California Central Valley, the buckling of highways in West Sacramento, and the cancelation of 50 flights out of Phoenix Sky Harbor Airport for American Airlines alone.

    While high temperatures are typical of the low-humidity pre-monsoon season in the Southwest, the unprecedented magnitude of these numbers and the shift towards an earlier extreme heat season may be a signal of the changing climate.

Greenland’s wildfires, as seen from space. Photo: NASA

JULY

  1. Once-icy Greenland engulfed in flames – In historically icy Greenland, wildfires have typically been of minimal concern. As a result, when the largest wildfire in the country’s history broke out at the end of July, there existed virtually no framework to assess the event’s health and infrastructure risk.

    As global temperatures rise and Greenland’s ice melts, the once barren landscape can fill with vegetation and expand the likelihood of forest fire outbreak. Climate change simultaneously lengthens and intensifies drought in the region, while increasing the likelihood of thunderstorms (a major catalyst of wildfires). Wildfires in turn intensify regional warming, as the fires’ soot deposits black carbon on the pristine snow cover, reducing the region’s reflectivity and accelerating ice sheet melt.

  2. “Lucifer” plagues Europe – Europe’s most sustained extreme heat event since the deadly 2003 heatwave (in which climate change was responsible for half of the 1050 recorded deaths) brought temperatures so reminiscent of the Inferno that locals named the event “Lucifer.” As temperatures throughout the region surpassed 104 degrees Fahrenheit, two deaths were recorded and a 15 percent increase in hospital emergency emissions was observed in Italy. The heatwave also caused pollution levels to soar and spurred wildfires throughout Portugal, just a few months after fires in Pedrógão Grande killed 60 and injured more than 250.

    Research concerning previous extreme heat in Europe has shown that climate change renders the maximum summer temperatures observed in regions such as Spain 500 times more likely than in the pre-industrial era. As global temperatures continue to rise, extreme heat will only become more familiar.

  3. Southeast Asia inundated by widespread floods – More than 41 million people were affected by massive floods and landslides that rippled through nations including Bangladesh, India, and Nepal. Losses experienced by the region included more than 1,300 lives and the displacement of 600,000. Two simultaneous pressures – the push for urbanization and neglect towards developing sustainable draining systems – renders the region highly vulnerable to these natural disasters.

    The link between the Southeast Asian monsoon season and climate change is complex, dependent upon a variety of entwined weather systems and intricate regional topography. More study is necessary to predict the influence of a changing climate on this monsoon system in order to prepare the region for impact and increase communities’ resilience.

Puerto Rico after Hurricane Irma. Photo: U.S. Customs and Border Protection

AUGUST

  1. Atlantic hurricane season leaves devastation in its wake – Deadly storms Harvey, Irma, Maria, and Ophelia dominated the news in August, killing more than 150 people and causing more than $300 billion in damages in just the United States.

    As the atmosphere holds seven percent more moisture with each one degree Celsius temperature rise, individual tropical storms can now deposit more rainfall. Recent studies have estimated that climate change rendered Harvey’s extreme rainfall three times more likely and 15 percent more intense. 27 trillion gallons of rain fell over Texas and Louisiana from Hurricane Harvey alone, setting the record for the highest tropical cyclone rainfall in the continental US. Sea level rise of 10 to 12 inches in cities such as Miami dramatically increased the destruction caused by the storm surges associated with Hurricane Irma, which were as high as 10 feet. Warming waters driving hurricane development and strength ushered in Hurricane Maria – Puerto Rico’s strongest storm in 85 years – and Hurricane Ophelia, which set records for the farthest east a major hurricane has traveled in the Atlantic and the worst storm in history to make landfall in Ireland.

OCTOBER

  1. Western United States’ forests set ablaze – Wildfires devastated Northern California this October, with more than 245,000 acres burned and 14,000 homes destroyed. Insured losses in the region amounted to more than $3 billion, but danger does not end when the fires are extinguished. The remaining ash and debris (including hazardous waste, electronic waste, and heavy metal contamination) can be spread by wind and rain, posing even further health concerns to those nearby. The increased temperatures and decreased water availability associated with climate change increases the risk of wildfires. Due to recent temperature and dryness extremes in California, even engine heat from parked cars has been cited as the source of major fires.

    The duration of the fire season has also begun to lengthen, as spring and summer temperatures rise and snowmelt begins earlier. California wildfires ignited once again in December outside of Los Angeles, creating even more destruction than those in the north. Covering an area of more than 425 square miles and displacing more than 100,000 people, the Thomas fire ranks as the second largest fire in the state’s history. While dryness and high temperatures triggering the fire’s outbreak are associated with La Niña’s current presence in the region, climate change serves to exacerbate both conditions and facilitate the dramatic losses experienced by California residents.

The direct influence of climate change on many of these events suggests that more devastating catastrophes lie ahead. But the future is not written in stone.

Should we recognize the intensification of these extreme weather events, the power to decrease greenhouse gas emissions worldwide and prevent increasingly hostile weather remains in our hands.

Also posted in Basic Science of Global Warming, Extreme Weather, Science / Read 2 Responses

Everything you need to know about climate tipping points

By Casey Ivanovich / Published: November 1, 2017

(This post was co-authored by EDF Climate Scientist Ilissa Ocko)

Imagine cutting down a tree. Initially, you chop and chop … but not much seems to change. Then suddenly, one stroke of the hatchet frees the trunk from its base and the once distant leaves come crashing down.

It’s an apt metaphor for one of the most alarming aspects of climate change – the existence of “tipping elements.”

These elements are components of the climate that may pass a critical threshold, or “tipping point,” after which a tiny change can completely alter the state of the system. Moving past tipping points may incite catastrophes ranging from widespread drought to overwhelming sea level rise.

Which elements’ critical thresholds should we worry about passing thanks to human-induced climate change?

You can see the answer on this graphic – and find more information below.

The most immediate and most worrisome threats

  • Disappearance of Arctic Summer Sea Ice – As the Arctic warms, sea ice melts and exposes dark ocean waters that reflect sunlight much less efficiently. This decreased reflectivity causes a reinforcement of Arctic warming, meaning that the transition to a sea-ice free state can occur on the rapid scale of a few decades. Some scientists have suggested that we have already passed this tipping point, predicting that Arctic summers will be ice-free before mid-century.
  • Melting of the Greenland Ice Sheet – The Arctic warming feedback described above may one day render Greenland ice-free. Research predicts that the tipping point for complete melt can occur at a global temperature rise of less than two degrees Celsius – a threshold that may be surpassed by the end of this century. While the full transition to an ice-free Greenland will take at least a few hundred years, its impacts include global sea level rise of up to 20 feet.
  • Disintegration of the West Antarctic Ice Sheet – The bottom of this ice sheet lies beneath sea level, allowing warming ocean waters to slowly eat away at the ice. There is evidence that this tipping point has already been surpassed – possibly as early as 2014. Like the Greenland Ice Sheet, full collapse would require multiple centuries, but it could result in sea level rise of up to 16 feet.
  • Collapse of Coral Reefs – Healthy corals maintain a symbiotic relationship with the algae that provide their primary food source. As oceans warm and become more acidic, these algae are expelled from the corals in an often fatal process called coral bleaching. Research predicts that most of our remaining coral systems will collapse even before a global temperature rise of two degrees Celsius.

Tipping points in the distant future

  • Disruption of Ocean Circulation Patterns – The Thermohaline Circulation is driven by heavy saltwater sinking in the North Atlantic, but this water is becoming fresher and lighter as glaciers melt in a warming climate. The change in water density may prevent sinking and result in a permanent shutdown of the circulation. Research suggests that weakening of the Thermohaline Circulation is already in progress, but that an abrupt shutdown is unlikely to occur in this century. Some models suggest that these changes may prompt a secondary tipping element in which the subpolar gyre currently located in the Labrador Sea shuts off. Such a change would dramatically increase sea level, especially on the eastern coast of the United States.
  • Release of Marine Methane Hydrates – Large reservoirs of methane located on the ocean floor are stable thanks to their current high pressure-low temperature environment. Warming ocean temperatures threaten the stability of these greenhouse gas reservoirs, but the necessary heat transfer would require at least a thousand years to reach sufficient depth, and may be further delayed by developing sea level rise.
  • Ocean Anoxia – If enough phosphorous is released into the oceans – from sources including fertilizers and warming-induced weathering, or the breakdown of rocks –regions of the ocean could become depleted in oxygen. However, this process could require thousands of years to develop.

Potentially disastrous elements, but with considerable uncertainty

  • Dieback of the Amazon Rainforest – Deforestation, lengthening of the dry season, and increased summer temperatures each place stress on rainfall in the Amazon. Should predictions that at least half of the Amazon Rainforest convert to savannah and grasslands materialize, a considerable loss in biodiversity could result. However, the dieback of the Amazon Rainforest ultimately depends on regional land-use management, and on how El Niño will influence future precipitation patterns.
  • Dieback of Boreal Forests – Increased water and heat stress could also lead to a decrease in boreal forest cover by up to half of its current size. Dieback of boreal forests would involve a gradual conversion to open woodlands or grasslands, but complex interactions between tree physiology, permafrost melt, and forest fires renders the likelihood of dieback uncertain.
  • Weakening of the Marine Carbon Pump – One mechanism through which oceanic carbon sequestration takes place is the marine carbon pump, which describes organisms’ consumption of carbon dioxide through biological processes such as photosynthesis or shell building. As ocean temperatures rise, acidification progresses, and oxygen continues to be depleted, these natural systems could be threatened and render the carbon sequestration process less efficient. More research is necessary in order to quantify the timescale and magnitude of these effects.

Tipping elements complicated by competing factors

  • Greening of the Sahara/Sahel – As sea surface temperatures rise in the Northern Hemisphere, rainfall is projected to increase over the Sahara and Sahel. This increased rainfall would serve to expand grassland cover in the region, but is balanced by the cooling effect of human-emitted aerosols in the atmosphere.
  • Chaotic Indian Summer Monsoon – The fate of the Indian Summer Monsoon similarly depends upon a balance of greenhouse gas warming and aerosol cooling, which strengthen and weaken the monsoon, respectively. On the timescale of a year, there is potential for the monsoon to adopt dramatic active and weak phases, the latter resulting in extensive drought.

More research necessary to establish as tipping elements

  • Collapse of Deep Antarctic Ocean Circulation – As in the case of the Thermohaline Circulation, freshening of surface waters in the Southern Ocean due to ice melt may slowly alter deep water convection patterns. However, the gradual warming of the deep ocean encourages this convection to continue.
  • Appearance of Arctic Ozone Hole – Unique clouds that form only in extremely cold conditions currently hover over Antarctica, serving as a surface for certain chemical reactions and facilitating the existence of the ozone hole. As climate change continues to cool the stratosphere, these “ice clouds” could begin formation in the Arctic and allow the development of an Arctic ozone hole within a year.
  • Aridification of Southwest North America – As global temperatures rise, consequential changes in humidity prompt the expansion of subtropical dry zones and reductions in regional runoff. Models predict that Southwest North America will be particularly affected, as moisture shifts away from the southwest and into the upper Great Plains.
  • Slowdown of the Jet Stream – A narrow and fast moving air current called a jet stream flows across the mid-latitudes of the northern hemisphere. This current separates cold Arctic air from the warmer air of the south and consequentially influences weather in its formation of high and low pressure systems. A slowing of the jet stream has been observed over recent years. Should slowing intensify, weather patterns could persist over several weeks with the potential to develop into extended extreme weather conditions.
  • Melting of the Himalayan Glaciers – Several warming feedbacks render the Himalayan glaciers vulnerable to dramatic melt within this century, though limitations on data availability complicate further study. Dust accumulation on the mountainous glaciers and the continual melt of snow and ice within the region both prompt a decrease in sunlight reflectivity and amplify regional warming.

Gradual, continuous changes

  • More Permanent El Nino State – 90 percent of the extra heat trapped on Earth’s surface by greenhouse gases is absorbed by the oceans. Though still under debate, the most likely consequence of this oceanic heat uptake is a gradual transition to more intense and permanent El Nino/Southern Oscillation (ENSO) conditions, with implications including extensive drought throughout Southeast Asia and beyond.
  • Permafrost Melting – As global temperatures rise and the high latitudes experience amplified warming, melting permafrost gradually releases carbon dioxide and methane into the atmosphere and creates a feedback for even more warming.
  • Tundra Transition to Boreal Forest – Much like the conversion of the Amazon Rainforest and boreal forests to other biomes, tundra environments may transition into forests as temperatures increase. However, this process is more long-term and continuous.

With a range of critical thresholds on the horizon, each tipping element demonstrates the potential implications of allowing climate change to progress unchecked.

As tipping points loom ever closer, the urgency for emissions mitigation escalates in hopes of sustaining the Earth as we know it.

Also posted in Basic Science of Global Warming, Extreme Weather, Oceans, Science / Comments are closed

A real Halloween horror story: the five scariest aspects of climate change

By Casey Ivanovich / Published: October 30, 2017

Halloween has arrived, and it’s time once again for goblins, gremlins, and ghost stories.

But there’s another threat brewing that’s much more frightening – because it’s real.

An unrecognizable world is quickly creeping up on us as climate change progresses – and the anticipated impacts are enough to rattle anyone’s skeleton.

Here are five of the scariest aspects of climate change. Read on if you dare ….

  1. Extreme weather is becoming more extreme

A changing climate paves the way for extreme weather events to live up to their name.

In 2017 alone we saw fatal events worldwide, including:

The fingerprints of climate change can be found on each of these events.

As global temperatures continue to rise, heat waves are expected to become more intense, frequent, and longer lasting.

Scientists also predict that rainfall patterns will continue to shift, increasing regional risk for widespread drought and flooding.

Montana, 2002. Photo: U.S. Forest Service

Drought conditions may also prompt wildfires to occur more frequently and within a longer fire season. The wildfire season in the western U.S. is already weeks longer than in previous years.

Hurricanes are also influenced by climate change. Rising sea surface temperatures, a moister atmosphere, and changing atmospheric circulation patterns have the potential to increase hurricanes’ power and travel paths.

Extreme weather intensification impacts human health and development in many ways – extreme heat events directly generate health hazards such as heat stroke, while drought and wildfires threaten crop and ecosystem stability.

The 2017 hurricane season has already demonstrated the shocking consequences of intensified hurricanes and flooding, with Hurricanes Harvey, Irma, and Maria killing more than 150 people and causing as much as $300 billion in damages in the U.S. alone.

  1. Tipping points loom in near future

A particularly alarming facet of climate change is the threat of irreversible changes to climate conditions, called “tipping elements.”

These components of the climate system earn their title from a possession of critical thresholds, or “tipping points,” beyond which a tiny change can dramatically alter the state of the system.

Many tipping elements have been identified by scientists, and some may have already passed their critical threshold. For example, a vicious cycle of sea ice melt has already been triggered, leading scientists to predict that Arctic summers will be ice-free before mid-century.

Imminent tipping points also exist for melting ice sheets, particularly those of Greenland and West Antarctica, where full ice sheet collapse could result in global sea level rise of up to 20 feet and 16 feet respectively.

Coral reefs too are rapidly approaching a grave tipping point. Essential relationships between algae and corals begin to break down as ocean waters rise in temperature and acidity. Without stabilizing these changes, the majority of global reef systems may collapse before global temperatures reach a two-degree Celsuis warming threshold.

  1. Coastal communities battle sea level rise

Sea level rise is one of the most visible impacts of climate change, as increased coastal erosion physically erases continental borders.

As the climate warms, ocean waters expand and ice sheets and glaciers melt. Both factors contribute to a rising sea level at an accelerating rate. Communities in Alaska and several Pacific Islands are already fleeing rising seas – relocating as their villages are engulfed and eroded.

Rising sea levels also intensify damages from extreme weather events such as hurricanes. A higher sea level allows storm surges to grow in height and volume, exacerbating flooding and associated damages.

As water levels continue to rise, more coastal communities will feel the consequences. Many major cities are located on coastlines, with almost 40 percent of U.S. citizens living in coastal cities.

Protecting people from this creeping threat will be difficult and costly – as we’ve already seen in the aftermath of coastal storms such as Superstorm Sandy.

  1. Humans are nearing uncharted climate territory

A globally averaged two-degree Celsius (or 3.6 degrees Fahrenheit) of warming over preindustrial levels is the most widely suggested threshold we need to stay “well” below.

The threshold was first proposed by William Nordhaus in the 1970’s, in part because of its historical significance – the human species has never lived during a time in which global temperatures were equivalent to two-degrees Celsius above preindustrial levels.

The unprecedented nature of this benchmark provided a foundation for alarm that carried the two-degrees Celsius value into political and scientific discussions for decades.

In a changing climate, unprecedented events will become the norm.

In some cases, they already have.

As infectious diseases spread to previously untouched regions and an Arctic ozone hole threatens to open, people are beginning to catch the first glimpses of the new world we are creating – one that is in many ways more hostile and dangerous than the one we leave behind.

  1. Many American politicians deny the problem

Perhaps the only thing more terrifying than the impacts of climate change is the overwhelming denial of their existence by some political leaders in the U.S.

The Paris Agreement served as a major step forward in promoting climate change mitigation policy on an international scale, with almost every nation agreeing to tackle this looming threat.

Then in June, President Trump announced his intent to withdraw from the agreement. That means the United States will be one of only two countries – out of almost 200 – failing to participate in the accords.

The same efforts towards dismantling U.S. climate progress can be seen in recent national policy. Environmental Protection Agency Administrator Scott Pruitt (who recently claimed that carbon dioxide is not a major contributor to global warming) is perhaps the most visible of an exhausting list of leaders within the current Administration who deny climate science. The Administration is trying to undermine or reverse policies addressing climate change, including the Clean Power Plan, and information about climate change is vanishing from official agency websites.

The rest of the globe is striving to implement meaningful climate policy, including China’s unparalleled growth in renewable energy support. Soon the U.S. will be left in the dust in the race for a greener world.

Be afraid. Be very afraid. Then do something about it.

We can’t protect you from the monsters hiding under your bed. But combating the ominous impacts of climate change is a much more hopeful endeavor.

For more information on how you can help, click here.

 

Also posted in Basic Science of Global Warming, Extreme Weather, International, News, Oceans, Policy, Science / Read 2 Responses

Huge Antarctic iceberg breaks off. Here’s why it worries scientists.

By Ilissa Ocko / Published: July 13, 2017

The massive rift in the Antarctic Peninsula’s Larsen C ice shelf, photographed by NASA scientists in November 2016. Photo by Stuart Rankin.

This post was co-authored by Mason Fried, a Ph.D. student of glaciology at the University of Texas Institute for Geophysics. It originally appeared on EDF Voices.

Scientists watched with alarm this week as the fourth-largest ice shelf in Antarctica rapidly broke apart, causing an enormous, Delaware-size iceberg to float into the Southern Ocean.

Scientists had been observing the anomalous rift widening across a section of the so-called Larsen C ice shelf for the past several years. Now they’re left with some critical questions: What are this event’s broader consequences for the Antarctic ice sheet, what happens next, and – importantly – what role did climate change play here?

Antarctica: A frontline for climate change

So far, scientists have been hesitant to attribute the Larsen C ice shelf breakup to rising global temperatures.

Indeed, such events – known to scientists as “calving” – occur naturally and are essential for maintaining ice shelf balance. Without them, ice shelves would grow unabated to cover large swaths of the Southern Ocean.

Still, the magnitude and timing of this ice loss warrants attention.

The Antarctic Peninsula, where the Larsen ice shelves reside, has long been viewed as a frontline for climate change. Warming in the peninsula exceeds the global average, glaciers there are retreating, and two other ice shelves on the peninsula already collapsed over the past couple of decades after being stable for thousands of years.

Such changes will help raise global sea levels by 3 to 6 feet by 2100, projections show, affecting dense coastal communities along our Eastern seaboard and across the globe.

Ice breakup starts chain reaction

We do know that this latest ice separation could set in motion a string of chain reactions that further destabilize the ice shelf and surrounding glaciers, and ultimately contribute to global sea level rise.

Ice shelves are floating extensions of grounded glaciers and ice sheets that, importantly, buttress and impede inland ice flow. When an ice shelf collapses or becomes weaker, this defense disappears, allowing inland glaciers to accelerate downslope and transport more ice to the ocean, which can quickly affect sea level.

Scientists worry that the remnant Larsen C ice shelf will now be at considerable risk of further breakup.

The new ice berg reduced the ice shelf area by more than 12 percent when it broke off, leaving behind an ice shelf that is inherently unstable. This can, in turn, trigger new ice cracks and rifting, and cause more icebergs to break off – further increasing the possibility of runaway ice loss amid rising global temperatures.

Whether or not this latest calving event will be attributed to climate change, it’s safe to say that it will make the region more vulnerable to the impacts of global warming.

Climate change caused 2002 ice shelf collapse

The Larsen C ice shelf, named for a Norwegian whaling vessel captain who sailed the Southern Sea in the late 1800s, has two smaller northern neighbors known as Larsen A and Larsen B – both of which collapsed in the past 23 years.

Those events taught us that ice sheets, landscapes we used to think of as stable and slow to change, can actually transform rapidly.

The Larsen B collapse was particularly dramatic, with nearly the entire ice shelf disintegrating during a three-week period in 2002 after remaining stable for at least 10,000 years.

The speed of that event was unprecedented and attributed directly to increasing atmospheric warming, although rising ocean temperatures and long-term ice loss from surrounding glaciers may also have played a role.

A hint of what’s to come?

After the Larsen B shelf collapse, researchers observed dramatic increases in glacier speed, thinning and ice transfer to the ocean.

Some researchers are already drawing parallels between this week’s Larsen C collapse and the series of events that led to the eventual collapse of Larsen B. The latter experienced a similar large calving event in 1995 that foreshadowed further retreat and widespread disintegration in 2002.

While it remains to be seen if and when Larsen C will meet the same fate, warning signs are already in place. What’s happening to the Larsen ice shelves could, in fact, be a proxy for what’s to come across even larger sections of the Antarctic ice sheet unless we take action to slow warming.

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