When fossil fuels are extracted and burned such as coal or petroleum, carbon dioxide and other heat-trapping “greenhouse gases” are released into the atmosphere. The atmospheric greenhouse effect naturally keeps our planet warm enough to be livable. Sunlight passes through the atmosphere. Light-colored surfaces, such as ice caps, radiate some heat back into space. But most of the incoming heat warms the planet's surface. The Earth then radiates some heat back into the atmosphere. Some of that heat is trapped by greenhouse gases in the atmosphere, including carbon dioxide
About half of the past century's rise in sea level is attributable to warmer oceans simply occupying more space.
Some of the human activity that is causing sea levels to rise and the surface temperature to rise has caused the planet to warm by 1.4 degrees since 1880 and the oceans absorb about 80 percent of this additional heat.
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Why Are Sea LEvels Rising?
Rising temperatures are warming ocean waters, which expand as the temperature increases. This thermal expansion was the main driver of global sea level rise for 75 - 100 years after the start of the Industrial Revolution, though its relative contribution has declined as the shrinking of land ice has accelerated.