The accelerated retreat of the ice sheets in Greenland and Antarctica could leave Millions of people are exposed to extreme scenarios. An analysis conducted by Inès Otosaka, Assistant Professor of Physical Geography and Environmental Sciences at Northumbria University (Newcastle), and published by The conversation warns that three unstable mechanisms resulting from rising temperatures could trigger a massive collapse of these ice giants, with irreversible consequences for the environment. sea level on a global level.
The ice sheets of Greenland and Antarctica are particularly vulnerable to rising temperatures. International teams supported by the European Space Agency (ESA) have used satellite data to identify retreating and thinning glaciers, a sign that some of these processes are already active.
He Intergovernmental Panel on Climate Change (IPCC) estimates sea level could rise between 0.3 and 1.6 meters by 2100. Despite it, If the instability mechanisms were fully activated, the rise would exceed 15 meters by the year 2300. Likewise, they estimate that the contribution of ice sheets to sea level rise could be dramatic by the year 2300 and that for every centimeter of rise, Six million additional people are at risk of coastal flooding.
- Instability of the sea ice cover (Misi): This phenomenon occurs when the seafloor beneath the ice sheet tilts inland, allowing the ice to quickly migrate into the ocean. In Antarctica, the weakness of the floating platforms favors this process and makes it irreversible. The expert quoted in The conversation warns that glaciers such as Pine Island and Thwaites in West Antarctica have already shown retreat, thinning and increased speed of movement, clear symptoms of the active presence of this mechanism.
- Instability of sea ice cliffs (Mici): It occurs when the cliffs left after an ice shelf breaks up exceed a certain height, lose stability and collapse due to internal effects such as hydraulic fracturing. This process can expose even higher and more vulnerable walls, increasing the phenomenon. Currently it has only been detected in mathematical models and its actual effects are still being analyzed.
- Surface Fusion Instability (Semi): It occurs when melting on the surface of the ice sheet reduces its height, meaning the ice is increasingly exposed to warm air and loses mass more quickly. Greenland is particularly at risk because surface melting has increased over the past decade and is the main cause of ice loss. Otosaka points out that susceptibility to heat increases at lower altitudes.
The most threatened regions include: West Antarcticawith some of the fastest glaciers in the world, and Greenland, where surface melting predominates. Satellite observations and models allow identifying critical points and predicting possible future activations of these processes. The retreat of Pine Island and Thwaites is particularly alarming in West Antarctica, while surface melting is the focus of attention in Greenland.
The self-sustaining activation of these mechanisms could alter the dynamics of polar ice, leading to irreversible retreat and sea level rise much faster than expected. Although the global collapse would take centuries, models using the Mici mechanism predict significant setbacks in less than 300 years.
By the year 2300, ice sheets could contribute to sea level rise dramaticwhich increases the risk of flooding to the population. As relevant information, although he already said: For every inch the sea rises, six million more people are at risk of coastal flooding.
The latest report from the IPCC reiterates that the estimated sea level rise by 2100 will be between 0.3 and 1.6 meters due to future greenhouse gas emissions. However, values greater than 15 meters cannot be ruled out by the year 2300, when the instability mechanisms fully develop.
Research remains active and evolving. International groups supported by the European Space Agencycross satellite data with numerical models to determine the critical threshold that would mark the start of irreversible ice sheet retreat.
Although certain self-sustaining dynamics have already been established, significant uncertainties remain, particularly regarding ice cliff instability. Some recent simulations suggest that the collapse may not be as abrupt as thought, reinforcing the need to improve knowledge on the subject.
Through a deeper understanding of these processes, it will be possible to anticipate specific risks and define strategies that reduce the human, social and economic impacts associated with the increase Coastal floodingStorms and population displacements.
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