Question: Will the polar ice caps melt? If they do what will happen and how fast would it happen?

Hayley Evers-King answered on 16 Mar 2013:

At the moment all the evidence suggests that the polar ice caps (particularly in the North) are melting. What will happen depends on which parts of the ice melt and how fast and also what is happening in the rest of the world. If the ice on land melts, this will run in to the sea and sea levels will rise. If the sea ice (that floats on the water) melts, then sea level doesn’t rise (the ice displaces the same volume of water), but this can cause other problems. How much the sea level rise will effect different places depends on their geology – how close to sea level their coasts are for example. Sea level can also rise due to increases in temperature – so if warmer temperature are causing ice to melt, they will also be causing sea levels to rise through expansion of warming water.

The input of cold and fresh water may effect ocean currents (if you’ve seen the film “the day after tomorrow” this is what inspired this movie). As ocean currents play a big role in heat distribution and weather, we may see changes in this too.

As ice is white, it reflects a lot of the suns energy back to space. This effect is known as ‘albedo’. Sea water on the other hand is very dark and absorbs a lot of heat. So a change in the amount of ice vs open sea can affect how much heat the Earth stores.

Ice is also a habitat for many species such as polar bears and seals and plays an important role in the many other animals food supplies. We’re not yet sure how well these animals will be able to adapt to an environment with less ice.

How fast all this will happen will depend on how fast the ice melts which depends partly on temperature. Many scientists are studying ice in these regions to see how they are reacting to warmer temperatures, which is often not very straightforward.