What are the projections for global temperature change and sea level rise?

Not everyone will be affected by climate change in the same way. Climate change will have different impacts depending on location, meaning that some people will be more severely affected than others.

By 2100, it is estimated that global average temperatures will be between 1.1 and 5.4°C warmer than presently recorded. Sea level is also expected to rise further, between 30cm and 1 meter. Even a small increase in sea level could have devastating impacts on low-lying island nations such as Kiribati.

There is a range of potential consequences of climate change to be aware of:

• Reduction in biodiversity on land and in the oceans
• Droughts could become more frequent and last longer
• Precipitation could become more frequent and heavier, leading to more flooding
• Melting glaciers could cause water supply issues
• A rise in sea level could lead to more coastal flooding
• Increased destruction caused by more substantial and more frequent cyclones
• Pests and associated diseases could become more widespread
• A change in farming practices to try to tackle climate change could lead to issues in the food supply chain

Projections for sea level rise

Sea level rise is considered to pose the biggest threat, with 23% of the world’s population living within 100km of coastline. There are many major cities located in coastal regions, such as New York, Miami, and Cairo, but the majority of those affected live in small coastal settlements.

A 1-meter rise in sea level would see devastating consequences for coastal regions, with some areas being submerged completely.

• The low-lying island nation of the Maldives could be entirely submerged.
• The low-lying nation of Bangladesh could lose 17% of its land, 50% of its valuable farmland. This would lead to tens of millions of displaced people requiring new homes and employment opportunities.
• The building of sea defences in rural and urban areas will cost millions to construct. In the USA alone, it would cost US$200 billion to protect its major cities.
• Coastal flooding will contaminate farmland and groundwater supplies with saltwater, limiting the availability of resources in affected regions.

There are many variables to consider when predicting sea level rise, making it difficult to predict how much the sea level could rise.

If greenhouse gas emissions continue to rise unchecked, it could lead to devastating increases in sea level. The graph below illustrates various outcomes related to greenhouse gas emissions.

Sea level rise will be impacted by melting sea ice and ice sheets. If Greenland’s ice sheet were to melt, this would raise sea level by 7 meters; if Antarctica’s ice sheet melted, this would add a staggering 13 meters to sea levels. Despite these scary figures, it will likely take many centuries for these ice sheets to melt entirely.

Prevailing winds, currents, and sinking land will influence where sea level rise impacts the most. The USA’s Gulf Coast is densely populated and at a higher risk of rising sea levels.