Ice & Climate Change
Most of us do not live in polar regions. We do not come in contact with icebergs or ice sheets very often. Most of us have only seen these things in photographs. However, no matter where you live, the snow and ice of the Earth’s cryosphere have an impact on our climate.
You already know that turning up the heat will melt the ice. The effect of climate change on the cryosphere - the icy part of our planet is almost that simple.
Global temperatures are warming, and that warming is fastest at the poles. As a result, ice sheets and glaciers melt and shrink. And, because the cryosphere is so interconnected with other parts of the Earth system, what happens in the cryosphere affects the whole Earth. Much of this ice is in the Arctic and Antarctic, but the planet is affected by changes in these polar regions as the ice melts. So what happens in the cryosphere does not stay in the cryosphere.
Though it may seem like there is still lots of snow and ice in the polar regions, there’s much less of it than there used to be...
Sea ice forms and melts strictly in the ocean. And glaciers are formed on land. Icebergs are chunks of glacial ice that break off glaciers and fall into the oceans. When glaciers melt, because that water is stored on land, the runoff significantly increases the water in the ocean. Which contributes to many problems, including the rising global sea level. Sea ice, on the other hand, is often compared to ice cubes in a glass of water: when it melts, it does not directly change the level of water. Instead, depleting Arctic sea ice triggers a host of other devastating consequences—from depleting available ice on which walruses can haul out or polar bears hunt and more.
Losing ice caps effect on climate change...
Meltwater from the ice sheets and glaciers flows into the ocean, causing sea levels to rise. It can lead to flooding, habitat destruction, and other problems. Melting ice is bad news for several reasons:
Temperatures
The Arctic and Antarctic are the world’s refrigerators. Snow and ice reflect approximately 90% of the solar radiation that hits them. As global warming causes more snow and ice to melt each summer, the ocean and land underneath the ice gets exposed to the Earth’s surface. Because they are darker in colour, they absorb more incoming solar radiation and then release the heat into the atmosphere. It causes more global warming. In this way, melting ice causes more warming, and so, more ice melts. This phenomenon is known as feedback. According to a recent scientific study that used computer models to predict the future of Arctic sea ice, there may be no more sea ice left in the Arctic Ocean during summer within the next few decades.
The Coastal communities
Sea level has been rising about 1-2 millimetres each year as the Earth has become warmer. Some sea level rises are due to melting glaciers and ice sheets. It adds water to the oceans that were once trapped on land. Some glaciers and ice sheets are particularly vulnerable. Global warming has caused them to be less stable, to move faster towards the ocean, and add more ice into the water. Such areas with less stable ice include the Greenland Ice Sheet and the West Antarctic Ice Sheet. If the Greenland Ice Sheet melted or moved into the ocean, the global sea level would rise approximately 6.5 meters. If the West Antarctic Ice Sheet were to melt or move into the ocean, the global sea level would rise approximately 8 meters.
Food
Polar vortexes increased heat waves, and unpredictability of weather caused by ice loss are already causing significant damage to crops on which global food systems depend. This instability will continue to mean higher prices for you and growing crises for the world’s most vulnerable.
Shipping
As the ice melts, new shipping routes open up in the Arctic. These routes will be tempting time-savers, but incredibly dangerous. Imagine more shipwrecks or oil spills like the Exxon-Valdez in areas that are inaccessible to rescue or clean-up crews.
Wildlife
When there’s less sea ice, animals that depend on it for survival must adapt or perish. Loss of ice and melting permafrost spells trouble for polar bears, walruses, arctic foxes, snowy owls, reindeer, and many other species. As they are affected, so too are the other species that depend on them, in addition to people. Wildlife and people are coming into more frequent contact – and often conflict – as wildlife encroach on Arctic communities, looking for refuge as their sea ice habitat disappears.
Permafrost
Arctic ice and permafrost—permanently frozen ground for as much as 40,000 years —store large amounts of methane, a greenhouse gas contributing to climate change. When it thaws, that methane is released, increasing the rate of warming. This, in turn, causes more ice and permafrost to melt, releasing more methane and causing more melting. As we lose more ice quickly and see more rapid permafrost melt. Then we will start seeing the worst climate change predictions come true.
What Is happening to the ice around the world...
- Since 1992, Greenland and Antarctica have both lost ice overall, each losing more than 100 billion metric tons of ice per year on average.
- The global average sea level increased by about 3 inches overall.
Ice sheets naturally fluctuate with seasonal variations in temperature, precipitation, and other factors. The NASA JPL data points show types of seasonal patterns, particularly for Greenland. Nearly three decades of data show that the overall shrinking of the ice sheets far exceeds seasonal and year-to-year variations.
Arctic scenario
Polar sea ice melts each summer and reforms each winter—a freeze-thaw cycle that in the Arctic has been dramatically altered by global warming.
We lose Arctic sea ice at a rate of almost 13% per decade, and over the past 30 years, the oldest and thickest ice in the Arctic has declined by a stunning 95%. Not only is summer sea ice shrinking rapidly in the Arctic, but so is the average thickness of sea ice. Where in the past, some Arctic sea ice grew to 10 feet (3 meters) thick over multiple years, now much of the ice has only one year of growth, making it much more susceptible to melting in the summer. If emissions continue to rise unchecked, the Arctic could be ice-free in the summer by 2040. But what happens in the Arctic does not stay in the Arctic. Sea ice loss has far-reaching effects around the world. Some of the scary facts about arctic ice depletion are
- >10% - rate at which summer sea ice is disappearing per decade, threatening species like polar bears...
- 25,000 – polar bears in the wild today
- ¼ - the estimated proportion of the world’s untapped oil and gas reserves found in the Arctic. As the ice moves out, oil companies are moving in.
Antarctic scenario
Data source: Ice mass measurement by NASA's GRACE satellites. The gap represents the time between missions. Credit: NASA
The eastern two-thirds of Antarctica is covered by an ice sheet so large that if it melts the sea would rise by 52 metres. Most scientists had once thought this ice sheet was largely invulnerable to climate change, but not any more. Scientists measure changes in the volume of these ice sheets by estimating the mass input, mostly via snowfall, and the mass output, mostly melting snow and ice along with icebergs that break off and float away. The difference between input and output is known as the ice sheet’s “mass balance”, which is highly sensitive to climate change.
For 44 years, satellites have helped scientists track how much ice is floating on the ocean around Antarctica’s 18,000km coastline. The continent’s fringing waters witness a massive shift each year, with sea ice peaking at about 18m sq km each September before dropping to just above 2m sq km by February. But across those four decades of satellite observations, there has never been less ice around the continent than there was last week.
- In the southern hemisphere summer of 2022, the amount of sea ice dropped to 1.92m sq km on 25 February – an all-time low based on satellite observations that started in 1979.
- But by 12 February 2023, last year's record had already been broken. The ice kept melting, reaching a new record low of 1.79m sq km on 25 February and beating the previous record by 136,000 sq km – an area double the size of Tasmania.
Antarctic scientists are now scrambling to work out what’s happening. The drops in sea ice and the back-to-back record lows are clear signs that the climate crisis is beating down on the frozen continent.
Greenland scenario
Data source: Ice mass measurement by NASA's GRACE satellites. The gap represents the time between missions. Credit: NASA
NASA has discovered that Greenland has lost 5 trillion tons of weight since the early 2000s. It equates to an average of 277 gigatons (a gigaton is 1 billion tons) of mass loss every year. The findings, published in the journal Nature Geoscience, shed new light on the forces driving ice loss on the world’s second-largest ice sheet.
Warm air temperatures cause melting to occur on the surface of the ice sheet—that process accounts for about half the ice Greenland loses each year. The other half comes from glaciers at the ice sheet’s edge crumbling into the sea. Losses from these seaside glaciers have, until now, been mainly attributed to warm ocean waters licking at the edge of the ice. But the new research finds that rising air temperatures have a big influence as well. Warm air causes the surface of the ice sheet to melt, and that meltwater then runs off into the ocean. When that happens, it churns up the waters—and that turbulence helps heat rise from the depths of the ocean and warm up the waters coming into contact with the ice. That, in turn, melts the glaciers faster.
This is important because the ice sheets of Greenland and Antarctica store about two-thirds of all the fresh water on Earth. They are losing ice due to the ongoing warming of the Earth’s surface and ocean. Meltwater coming from these ice sheets is responsible for about one-third of the global average rise in sea level since 1993.
What should be done...
I find that global warming increases the decay of the cryosphere of the Earth. The disintegration of the Arctic summer sea ice and the retreat of mountain glaciers, Greenland and the West Antarctic Ice Sheets together cause an additional GMT increase of 0.43 °C (0.39–0.46 °C) for a baseline scenario of 1.5 °C warming above pre-industrial levels, which translates into additional warming of 29% (26–31%).
The findings come in a powerful new study by EDF researchers Tianyi Sun, Ilissa Ocko, and Steven Hamburg. This new study is one of the first to examine the climate impact of practical methane emissions reductions, beyond temperature rise. As global temperatures rise, the ice on the poles is rapidly declining. About 40% of Arctic summer sea ice has vanished since 1979. Projections from a recent Intergovernmental Panel on Climate Change report estimate it could disappear around mid-century.
Also, scientists predict polar bears will be wiped out by the end of the century without urgent action to tackle climate change. Such a loss would not only be tragic for polar bears, walruses and other species that depend on sea ice for survival. It would also further accelerate global warming. Sea ice reflects 50-70% of the sunlight that hits it. Ocean water, on the other hand, absorbs over 90% of sunlight. The more sunlight gets absorbed by ocean water, the more the Earth warms. Without sea ice, it could have the same warming impact as a trillion tons of carbon dioxide emissions. That’s 25 years' worth of warming at the world’s current emission rate.
Rapidly slashing the methane emissions all over the world could help save our Arctic summer sea ice, slow climate change and protect countless animals that make sea ice home. Over the following 20 years, the methane released today will cause 80 times more warming than an equal amount of CO2. So along with reducing CO2, cutting methane this decade gives us our best chance at preserving this vital part of our planet for generations to come. According to the study, net-zero CO2 emissions by 2050 (as laid out in the Paris Climate Agreement) combined with quick methane reductions, increase the odds of preserving sea ice this century from nearly zero to 80%.
If we do nothing, ice will likely vanish. If we hit net-zero carbon dioxide by 2050 but ignore methane, we have a 50-50 chance of preserving it. But if we tackle methane, too, we have a very good shot at saving this critical climate component that is vital to us all.
What you can do...
The key to saving sea ice for polar bears and getting the climate back to functioning the way it should is to get away from using fossil fuels for energy altogether. As scientist Katharine Hayhoe says, when it comes to global climate warming and a future for polar bears, “we need all options on the table and all hands on deck.” What are your options...???
- Vote and speak up. The most important action you can take is to vote with the climate in mind, in every election. Also, let your representatives know you support bold climate action. Tell your government you want them to back green energy – to fight climate change and stop the rush to exploit the poles.
- Support an energy shift. Get involved in community projects that reduce or replace fossil fuels with clean energy sources like solar and wind. Also, research renewable energy options available to you. Reducing your carbon emissions and dependence on fossil fuels can help save the ice on our planet.
- Talk about it! Open up and talk about climate change (and climate solutions) with friends, family members, and colleagues.
- Promote clean transportation. Support community projects aimed at reducing the number of vehicles overall, such as car-sharing and mass transit programs. Also, support the shift to electric and hybrid cars.
- Build a better future. Encourage energy-efficient construction standards, including better heating and cooling systems, insulation, and lighting methods. Discover practical ways which make a difference, from joining the campaigns to shopping greener at the supermarket and making your home energy efficient.
Stand up, raise your voice, and demand urgent, meaningful, and concrete climate action to keep the global temperature rise to 1.5C and help communities and wildlife adapt. The poles need our help today. Without careful planning, management and regulation, it affects all of us, no matter where we live.
Comments
Post a Comment