Ask a scientist

What is iceberg grounding?

Icebergs ‘ground’ on the ocean floor when their keel is deeper than the water depth. They may become stuck until high tide floats them off, or if they are washed into a shallow area, until they melt sufficiently to float away.

How are ice cores dated?

I was wondering how ice cores are dated accurately. I know Carbon 14 is one method, but some ice cores go back hundreds of thousands of years. Would other isotopes with longer half-lives be more accurate? Also, how much does it cost to date the core? How are samples acquired without destroying the ice? I …

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The news about the effect of climate change in the Arctic centres on the loss of polar bears. Will there be a similar effect with wildlife in the Antarctic?

Parts of Antarctica are warming rapidly, and this is affecting snowfall, snowmelt, sea ice distribution and thickness, and ice shelves. Different species are affected in different ways by these processes. Emperor penguins are often cited as one of the most vulnerable animals. Over the past 50 years, the population of Emperors in Terre Adelie has …

The news about the effect of climate change in the Arctic centres on the loss of polar bears. Will there be a similar effect with wildlife in the Antarctic? Read More »

What is the headwall of a glacier?

Asked by Haifeng The headwall of a glacier is the rocky wall at the top end (head) of a glacier. There are some nice illustrations here.

How is it possible that by decreasing pressure on an ablation area (due to stress reduction) an an enhancement on ice motion is obtained.

I’m trying to figure out how is it possible that by decreasing pressure on an ablation area (due to stress reduction) an an enhancement on ice motion is obtained. It would be very useful for me if you could explain it through a simple example cause I’m not a scientist. Thanks! Asked by Gus Dear …

How is it possible that by decreasing pressure on an ablation area (due to stress reduction) an an enhancement on ice motion is obtained. Read More »

How are icebergs made?

Asked by Yasmin Icebergs form when chunks of ice break off (‘calve’) from a glacier or ice shelf that ends in the ocean.

On average how long does it take for a glacier to build up before it starts to slowly move and slide? And how do Newton’s Laws affect a glacier the most?

Asked by Erik Hi Erik, The time taken for glacier ice to thicken sufficiently to start to move downslope will depend on: The rate at which snow builds up The slope of the ground. Small, simple glaciers are driven by the gravitational driving force ( τb), as given by the equation: τb = ρigh sin αS Where ρigh is …

On average how long does it take for a glacier to build up before it starts to slowly move and slide? And how do Newton’s Laws affect a glacier the most? Read More »

Is it possible that glaciers are showing a decrease in mass balance (not negative), yet they are showing recession

Asked by Murtaza Hi Murtaza, The easiest way to think about mass balance is to liken it to a bank account. If you consistently have more going out than coming in, over time your bank account will decrease in size. If you consistently pay in more than you spend, your bank account will grow. It …

Is it possible that glaciers are showing a decrease in mass balance (not negative), yet they are showing recession Read More »

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