Scientists studying Greenland have uncovered surprising heat variations deep beneath the ice that could reshape experts' understanding of future sea-level rise. 

What's happening?

The discovery, made using advanced 3D modeling of Earth's interior, highlights how unseen forces below the surface can influence ice-sheet behavior and the amount of water they may add to the oceans. 

A new study published in PNAS mapped temperature differences in the upper mantle beneath Greenland and Northeastern Canada. Researchers created detailed 3D models showing unexpectedly large fluctuations in underground temperatures by using satellite data, seismic readings, gravity measurements, and heat-flow records. 

These findings help trace Greenland's path over the Iceland hotspot, a massive region of heat rising from deep within Earth. They also reveal how this lingering warmth affects the way the land bends and shifts under the weight of ice. According to the researchers, these underground temperature differences can change how quickly bedrock rebounds as ice melts, a process known as glacial isostatic adjustment.

"This research advances our understanding of the Earth's internal structure beneath Greenland," University of Ottawa Professor Glenn Milne, the study's lead researcher, said in a press release.

Why is this finding important?

Greenland's ice sheet is already one of the largest contributors to rising sea levels worldwide, accounting for 20% of the current rise. While melting ice is driven by increasing global temperatures linked to human pollution from burning coal, oil, and gas, this study shows that what's happening beneath the ice also plays a major role. 

Warmer, softer rock in the hotspot beneath Greenland allows land to deform more easily as ice disappears, influencing how fast glaciers move and how much water reaches the ocean. That means projections of future sea levels could be off if underground heat and Earth's structure aren't fully accounted for. 

The ripple effects of rising seas are not isolated extreme weather events but an intensified pattern that can make storm surges and flooding more destructive, putting coastal communities, drinking water supplies, and infrastructure at risk, especially for communities with fewer resources to adapt.

What's being done about it?

Now, scientists will have better tools to more accurately predict future sea-level rise, helping policymakers and planners prepare for what lies ahead. Improved Earth and ice modeling supports the need for smarter coastal resilience strategies, such as flood defenses, wetland restoration, and updated building codes.

Reducing pollution from nonrenewable sources remains critical for slowing ice loss. Expanding renewable energy, electrifying homes and transportation, and supporting science-based policies can help limit future warming and the critical climate issues that follow.

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