It is ‘virtually certain’ that global mean sea levels are rising (Intergovernmental Panel on Climate Change). The change is also accelerating. Global mean sea levels increased from 1.4 mm per year (1901–1990) to 3.6 mm per year (2006–2015).
Sea levels are projected to rise by between 0.43 metres and 0.84 metres by 2100 depending on the Representative Concentration Pathway (model) used. Sea level rise is not the same around the world, due to climate variations it can be +-30% in different areas.
Glacier and ice sheet contributions are now the dominant source of sea levels rising. This is due to anthropogenic forcing (greenhouse gas emissions).
How high will sea levels rise?
If tipping points are reached, like if certain large ice masses start to melt, this change could accelerate dramatically (Sky News). The West Antarctic ice sheet could contribute up to 3.3 metres to sea levels. The Greenland ice sheet could raise sea levels by 7.4 metres, making a total of over 10 metres. This would affect over 600,000,000 people who live in coastal areas.
At COP26, Tuvalu’s foreign minister gave his speech while standing knee deep in water to demonstrate their plight. Coastal erosion is already a major problem in Tuvalu (UNDP).
Egypt, the current host of COP27, is expected to see severe and potentially catastrophic effects of sea levels rising (EESI). The UN says the Nile Delta, home to one in four people in Egypt and responsible for a large proportion of its gross domestic product, is one of “world’s most vulnerable areas when it comes to sea level rise.”
The ‘loss and damage fund’ is likely to be a hot topic at COP27 as nations who are affected by climate change events like drought, flooding and rising sea levels, will be asking for compensation from nations that have benefited economically from burning fossil fuels.
Sea levels are rising in the UK
Here in the UK, sea levels in the UK have already risen by approximately 16.5 cm. They are projected to rise by 11 centimetres a year by 2030 under a 2 degree warming scenario. This will increase to 19 cm a year by 2050 and 36 cm a year by 2100 (Met Office – PDF).
The projections depend on the location within the UK and the RCP scenario used. The worst case scenario for London suggests an 115 cm increase while the best case scenario in Edinburgh shows only 8 cm.
At a projected 35 cm increase, up to 300,000 homes could be at risk of flooding or coastal erosion in the UK (Tyndall). At 1 metre, large portions of London and areas on the south and east coasts of England would be under water (Climate Central).
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