A 2°C increase in temperature compared to pre-industrial times would cause sea level rise to be faster than a 1.5°C increase.

 

The faster the increase, the more flooding, salinization of freshwater and groundwater, land loss and destruction of coastal ecosystems on land. Small islands, low-lying coastal areas and deltas are particularly affected. These losses are irreversible.

On land, impacts on biodiversity and ecosystems, including species loss and extinction, are projected to be less at 1.5°C global warming than at 2°C. 

 

At 2 °C, out of 105,000 species studied, 18% of insects, 16% of plants and 8% of vertebrates lose more than half of their natural habitat. With a warming of 1.5 °C, it would only be 6% for insects, 8% for plants and 4% for vertebrates.

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At 2°C, terrestrial terrestrial ecosystems change into other types almost twice as fast as at 1.5°C.

Just like global warming, thesea level rise and accelerating the melting of glaciers and ice caps. From 1961 to 2003, global sea levels rose by about 1.8 millimeters per year. This rate increased to 3.1 millimeters between 1993 and 2003. Mountain glaciers and snow cover on Earth have decreased. Retreating glaciers and ice caps (excluding Greenland and Antarctica) caused sea levels to rise by 0.5 millimeters per year between 1961 and 2003 and by 0.77 millimeters per year between 1993 and 2003.

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Climate change is affecting entire continents and sea basins: average temperatures in the Arctic have risen twice as fast as the global average since about 1980 (SWIPA, 2011).

Thearctic sea ice is shrinkingin its average annual expansion by 2.7 percent per decade, in summer even by 7.4 percent per decade. It reached the previous record low of 3.41 million square kilometers on September 16, 2012. This is about 50 percent below the long-term mean of the minimum summer extents of the period 1979 to 2000 (NSIDC, 2012).

Extreme weather events and natural disasters are increasing every year. Unfortunately, 2020 was another extraordinary year for our climate. We have seen new extreme temperatures on land, at sea and especially in the Arctic. Wildfires consumed vast areas of Australia, Siberia, the US West Coast and South America, sending plumes of smoke circling the globe. We've seen a record number of Atlantic hurricanes, including an unprecedented Category 4 hurricane in Central America in November. Floods in parts of Africa and Southeast Asia resulted in massive population displacement and undermined the food security of millions.

 

Secretary General of the Global Meteorological Organization (GMO) Prof. Petteri Taalas.