Database results:
examBoard: Cambridge
examType: IGCSE
lessonTitle: Climate Change: Ice Melt and Sea Level Rise
Our planet's ice - from the vast polar ice caps to mountain glaciers - is melting at an unprecedented rate due to climate change. This melting ice contributes to rising sea levels, which threatens coastal communities, ecosystems and infrastructure worldwide.
Key Definitions:
The cryosphere (Earth's frozen regions) is particularly sensitive to climate change. For every 1°C rise in global temperature, we lose approximately:
Global sea levels have risen about 20cm since 1900, with the rate accelerating. Current projections suggest:
The Earth's ice is melting in several key regions, each with different impacts on sea levels and global systems.
Arctic sea ice floats on the ocean and its melting doesn't directly raise sea levels (like ice cubes melting in a drink). However, the loss of Arctic ice has serious consequences:
As white ice disappears, darker ocean water absorbs more heat, warming the Arctic further and causing more ice to melt - a dangerous cycle.
Arctic warming disrupts the jet stream, leading to more extreme weather events like heatwaves, cold snaps and storms across Europe and North America.
Species like polar bears, seals and Arctic foxes depend on sea ice for hunting and habitat. Many face extinction as their environment rapidly changes.
Unlike sea ice, these massive land-based ice sheets directly contribute to sea level rise when they melt. They contain enough water to raise global sea levels by over 65 metres if they were to melt completely.
Greenland's ice sheet is losing about 280 billion tonnes of ice per year - enough to raise global sea levels by 0.7mm annually. Summer melt seasons are becoming longer and more intense, with record-breaking melt events in 2012 and 2019.
Parts of Antarctica, particularly the West Antarctic Ice Sheet, are becoming increasingly unstable. The continent is now losing about 150 billion tonnes of ice annually, with some glaciers retreating by several kilometres per year.
Mountain glaciers worldwide are retreating rapidly, affecting water supplies for millions of people and contributing to sea level rise.
Since 1850, we've lost more than 50% of glacier ice in the European Alps and many tropical glaciers in places like Peru and Indonesia may disappear completely within decades.
These glaciers act as natural water towers, releasing meltwater during dry seasons. Their loss threatens water security for communities that depend on this steady supply.
Sea level rise is caused by two main factors:
Higher sea levels mean storm surges reach further inland, flooding areas that were previously safe. By 2050, annual coastal floods may affect 300 million people worldwide.
Rising seas push saltwater into coastal aquifers and farmland, contaminating freshwater supplies and making soil too salty for traditional crops.
Roads, buildings and utilities near coastlines face increased damage from flooding and erosion, costing billions in repairs and adaptations.
The Maldives, a nation of 1,200 islands in the Indian Ocean, is one of the most vulnerable countries to sea level rise. With an average ground level of just 1.5 metres above sea level, even modest rises threaten its existence.
The government has already had to relocate people from some outer islands and is considering purchasing land in other countries as a last resort. They've also built an artificial island called Hulhumalé with an elevation of 2 metres to house displaced citizens.
The Maldives spends around 27% of its GDP on climate adaptation measures like sea walls, beach nourishment and raised infrastructure - a massive economic burden for a small nation.
Scientists use several techniques to track ice melt and sea level rise:
Satellites like NASA's GRACE and ICESat measure changes in ice thickness and mass across large areas. They've revealed that Greenland lost about 3.8 trillion tonnes of ice between 1992 and 2018.
Networks of tide gauges around the world's coastlines provide long-term data on sea level changes. Some records date back to the 1800s, showing the acceleration of sea level rise in recent decades.
Communities worldwide are developing strategies to address rising seas:
Sea walls, surge barriers and raised buildings can protect against flooding. The Thames Barrier in London and MOSE project in Venice are examples of major engineering solutions.
Restoring coastal wetlands, mangroves and coral reefs provides natural protection against storms and erosion while supporting biodiversity.
Some communities are relocating away from high-risk coastal areas. In the UK, the village of Fairbourne in Wales is planned to be abandoned by 2054 due to sea level rise.
The Netherlands has been managing water for centuries, with about 26% of the country below sea level. Their approach combines:
The Dutch now export their water management expertise worldwide, showing how adaptation can create economic opportunities.
The future of ice melt and sea level rise depends largely on how quickly we reduce greenhouse gas emissions:
If emissions continue to rise, we could see:
If we rapidly reduce emissions in line with the Paris Agreement:
Even with immediate action, some sea level rise is already "locked in" due to the slow response of ice sheets and ocean warming. This makes adaptation strategies essential alongside emissions reduction efforts.
Understanding the science of ice melt and sea level rise helps us make informed decisions about both reducing emissions and preparing for the changes that are already underway.
Log in to track your progress and mark lessons as complete!
Login NowDon't have an account? Sign up here.