Antarctica shrinks – new estimates from satellite data

Substantial loss of ice-sheet mass has been confirmed for Greenland and West Antarctica, thanks to an innovative approach to data interpretation. The satellite data also showed that the contribution of the receding ice sheets to sea-level rise has accelerated over the past few years.

In 2002, twin satellites were launched to make detailed measurements of Earth’s gravitational field. Variations in the mass of the polar ice sheets — and more generally in the storage of water or ice on land — affect the gravitational field, and this is detected by the GRACE satellites.

The satellite data is complicated to interpret because melting ice isn’t the only cause of gravity changes. To make an accurate estimate of ice-sheet reduction, factors such as changes in oceanic and atmospheric distribution have to be disentangled.  

These new findings confirm the ongoing shrinkage of the polar ice sheets. However, the newly estimated ice-sheet mass losses are less than half of other recent GRACE-based estimates for the same time period. This suggests we have previously assumed that ice melting has more of a role in the changes in the gravitational field than it actually does – that’s why reanalysis of the same satellite data produced a different result.

The difference is that the latest studies used ground-based GPS data to reduce their reliance on deglaciation models. This extra data should increase the accuracy of estimates, but they suffer from the problem that there aren’t yet enough measurements. However, the network of GPS sites in Greenland and Antarctica has been considerably expanded since 2007 as part of an International Polar Year project. This will help improve our understanding of the polar ice sheets, and ensure measurements are increasingly accurate.

Bromwich DH & Nicolas JP (2010) Sea-level rise: Ice-sheet uncertainty Nature Geoscience doi:10.1038/ngeo946

GRACE satellites

Technological advances increase our knowledge of climate change. Does this mean what we ‘know’ about the climate isn’t accurate enough to go on? Or does it mean we should focus technology on dealing with the problem not just finding out more about it?


About Rebecca Nesbit

I am author of a popular science book 'Is that Fish in your Tomato?' exploring the fact and fiction of GM crops. In my work and leisure so far, I have trained bees to detect explosives, used a radar to study butterflies for my PhD, written a novel, taken the train from London to China, organised Biology Week, sold science jewellery on Etsy, and traveled to four continents with Nobel Laureates. Best off all, I've made lots of friends whose support I very much appreciate. Thank you! Please visit my website:
This entry was posted in Advances in technology, climate change. Bookmark the permalink.

4 Responses to Antarctica shrinks – new estimates from satellite data

  1. stephany daum says:

    some rich , powerfull, group must stop population growth now, we have run out of time. so has the planet. it really wont matter who had the correct politics or religion. because we will not be here as a species to talk about anything.

  2. emmalouisewright says:

    That is one of the arguments for war and natural disasters and the like, sort of population control. Let’s go looking for more WMDs or start world war thre, kill a few million people in the process and it’ll all work out nicely…

    (Because it’s hard to show sarcasm through text…I am not being entirely serious here!)

  3. War has other advantages – more innovation, increased sense of community. Shame about the bad points…

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s