The increasing global sea levels could see a rise of two metres (6.5 feet) by the end of the century, a projection that doubles the benchmark estimates given by the UN’s Intergovernmental Panel on Climate Change (IPCC). The scenario could result in displacing tens of millions of people. Leading ice scientists around the world have given their expert judgement on the situation.
Expert Analysis
These experts have drawn from their knowledge and observations to conclude that it is “plausible” that under the scenario where emission levels remain the same, sea-level rises could surpass two metres by 2100. The vast ice sheets in Antarctica and Greenland, if melted, contain enough frozen water to elevate the world’s oceans by several dozen metres.
Contributors to Sea Level Rise
There are two main contributors to sea level rise: thermal expansion of warming oceans and the melting of glaciers. Thermal expansion, which has been accurately quantified, remains as the current primary contributor and is expected to continue its dominance throughout the next century. Meanwhile, the significant contributions of glaciers are more challenging to predict and quantify. Projections for predicted sea level rise in the next century range between 90 to 880 mm, with 480 mm being the central value.
| Contributor | Current Contribution | Projected Contribution |
|---|---|---|
| Thermal Expansion | Primary Contributor | Expected Primary Contributor in Next Century |
| Glaciers | Significant But Difficult to Quantify | Significantly Harder to Predict in Next Century |
Revised IPCC Assessment
IPCC’s fifth assessment report indicated that if current emission trajectories persist, a likely rise of up to one metre by 2100 could occur. This initial prediction has been seen as conservative, given that greenhouse gas emissions levels continue to escalate annually and satellites display accelerated melt-off rates from the extensive ice sheets in Antarctica and Greenland.
Implications for Humanity
A sea-level rise of this magnitude will undoubtedly have significant implications for humanity. Approximately 1.79 million square kilometres of land are at risk of disappearance, with potential displacement of up to 187 million people. The situation is particularly dire for small island states, especially those in the Pacific, as it might render them uninhabitable.
Response from Governments
In response to these alarming projections, the Paris climate deal was established in 2015. This agreement aims to limit global temperature increases to well below two degrees Celsius (3.6 Fahrenheit) and encourages nations to strive towards a maximum increase of 1.5 degrees Celsius. In addition, the IPCC released a landmark climate report advocating for immediate reductions in coal, oil, and gas consumption to curb the rapid increase in greenhouse gases within the atmosphere.
