Ponds on ice- What I do and why (I think!) it matters

Melt ponds, which are exactly what the name implies – ponds of melted water formed on ice – have been observed in recent years on the Antarctic Peninsula, the most northern part of Antarctica. Previously this area had been too cold for melting to occur but, due to a 2.5 degrees Centigrade warming trend on the Peninsula over the last 50 years (several times the global average), this has begun to change.[1]

Melt ponds on Arctic sea ice such as those initially modelled by CPOM, copyright NASA Goddard Space Flight Center

Melt ponds on Arctic sea ice such as those initially modelled by CPOM, copyright NASA Goddard Space Flight Center

The Larsen B ice shelf on the Antarctic Peninsula hit the headlines in 2002 when it spectacularly (see image below- definitely a justified use of the word spectacular!) collapsed and an area of ice larger than Rhode Island was lost in a matter of weeks.[2] This collapse occurred during record warm air temperatures when both the length and extent of the melt season reached a new high. Areas of the ice shelf with melt ponds collapsed whereas adjacent areas with few or no melt ponds did not. This suggests that melt ponds may be playing a role in triggering ice shelf collapse. However, there are many other processes – such as rising ocean temperatures – which may also play a role and so a greater understanding of ice-shelves and the mechanisms affecting them is essential in predicting their future.

A common misconception is that when ice shelves collapse they contribute to sea level rise. This is not strictly true; ice shelves are already floating on the water and in the same way that when ice cubes in your glass of water melt the water level in the glass doesn’t go up, ice shelf break-up (and subsequent melting) won’t add to global sea level. By Archimedes’ Principle (that’s the one from the ‘jumping out of the bath shouting “Eureka”’ story) the floating ice has already displaced a volume of water that is virtually the same as the amount that would be added to the sea if the ice shelf were to melt.*

However, the fact that ice shelf break-up doesn’t contribute to sea level directly doesn’t mean that it doesn’t have an effect on it. When Larsen B broke up it was observed that the glaciers which fed into the ice sheet accelerated, possibly because there was no longer any force from the ice sheet blocking their flow. The ice coming from these glaciers is coming from the land and going into the sea so does contribute to sea level rise. This acceleration can continue for several years after the ice shelf has collapsed,[3] so the effect of a large collapse can actually be quite significant. On top of this, there is also the loss of habitat and the effect that large amounts of cold fresh water from the melted ice shelves have on ocean circulation and chemical make-up to be considered.

The break up of Larsen B in early 2002. The dark marks on the ice shelf you can see are melt ponds or drained melt ponds. Copyright NASA.

The break up of Larsen B in early 2002. The dark marks on the ice shelf you can see are melt ponds or drained melt ponds. Copyright NASA.

So what is it about these ponds makes them so key in understanding what will happen to the ice shelves? Firstly, it’s important to note that ‘pond’ is quite a deceptive term – on the Antarctic Peninsula we’re talking about something that can cover several square kilometers as oppose to something that would be found in your back garden, so these ponds are actually a fairly significant feature of the ice shelf.

One of the crucial things that melt ponds affect is albedo. Albedo is the proportion of incoming radiation that a surface reflects back. Ice, being white, has a high albedo whereas a melt pond is darker and has a lower albedo: it will reflect less energy and thus absorb more energy. Absorbing more energy means more heat is absorbed, more ice melts, ponds grow, albedo is further decreased, more energy is absorbed and so on in a positive feedback loop that results in greater and greater amounts of ice melting.

Meltwater is also thought to influence ice shelf break up when it fills crevasses in the ice. The forces that act on crevasses that open in the ice sheet tend to close them but meltwater filling existing surface crevasses provides an outward pressure that can allow them to remain open. Additionally, meltwater can cause the crevasses to penetrate further through the ice shelf, possibly far enough for them to reach the ice shelf’s base and impact on its structural integrity.[1]

greenlandponds_ali_2010185

A melt pond on the Greenland ice sheet- very similar to those I’m looking at and hopefully a lot of my work can be applied to Greenland too. Copyright NASA Earth Observatory.

Researchers in the group that I’m part of- Centre for Polar Observation and Modelling (CPOM) [4] at the University of Reading are looking at improving climate models by incorporating a better understanding of the processes affecting melt pond formation into the models. Initially, work was done on modelling melt ponds on Arctic sea ice [5]; one of the greatest uncertainties in predicting future global temperature changes is sea ice level fluctuations and this is something the level of melt ponds will play a role in. Now they have successfully incorporated a physically based melt pond scheme into the CICE sea ice model in order to simulate the stages of melt pond development.[6]

So where do I come into this? I’m going to be adapting a physical model of Arctic sea ice melt ponds to look at the Antarctic, focussing on the Larsen C ice shelf as melt ponds have appeared there and it is thought to be a potential candidate for future collapse. The ponds found on Antarctica are much larger and over a greater scale than the Arctic sea ice ones and, unlike sea ice, the ice-shelves do not contain salt, adding an extra challenge in modifying previous work. If successful this model will help to provide new insights into the role of meltwater in the collapse of ice shelves and help to improve future versions of ice sheet models and climate predictions. I’ll keep you updated.

*Technically, a very small amount of sea level rise would occur on melting as ice shelves are made of fresh water and sea water is salty (and therefore more dense than fresh water) so slightly less water is displaced than the total melted amount would add but the effect is so small it is negligible: the equivalent of less than 4cm of sea level rise if all floating ice (ice shelves and sea ice) were to melt.

References:

[1] Scambos et al. (2000), The link between climate warming and break-up of ice shelves in the Antarctic Peninsula, Journal of Glaciology, Vol. 46, No. 154, pg 516-529

[2] http://nsidc.org/news/press/larsen_B/2002.html

[3] Scambos et al. (2004), Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment Antarctica, Geophys. Res. Lett., 31, L18402, doi:10.1029/2006GL020670

[4] http://www.cpom.org/research.html

[5] Scott and Feltham (2010), A model of the three-dimensional evolution of Arctic melt ponds on first-year and multiyear sea ice, J. Geophys. Res., Vol.115, C12064, doi:10.1029/2010JC006156

[6] Flocco et al. (2010), Incorporation of a physically based melt pond scheme into the sea ice component of a climate model,  J. Geophys. Res., Vol.115, C08012, doi:10.1029/2009JC005568

Book Review- Cake Days from the Hummingbird Bakery

P1070934£20- Collins

My rating: 3/10

To quote the great Paul Hollywood this is definitely a “style over substance” book.

In my post about cocktail cupcakes I mentioned that I loved the hummingbird ideas but the reality was too sweet. They have lots of complicated and unhealthy ingredients and to be honest that seems to apply to most of the recipes in this book. The contents are beautiful, fun and original but generally you can do something similar for a fraction of the budget and calories. Some recipes such as the grasshopper pie have a horrendous amount of cream and the result was described as tasting like a bad Vienetta ice cream. I’d rather buy the ice cream, have my afternoon back and save my arteries at the same time.

P1070939 However, saying that it’s presented in a lovely seasonal way, there are loads of pictures which is always helpful and one recipe I did love is the spiderweb cheesecake: simple and not loads of ingredients for once!  

Verdict: Borrow someone else’s or get it out of the library- steal some ideas and create your own versions but the recipes themselves are not worth shelling out for.

My attempt at the spiderweb cheesecake with some other Halloween goodies.

My attempt at the spiderweb cheesecake with some other Halloween goodies.

Antarctica in the News- The Penguins Are In Trouble!

Headlines today have picked up on a study suggesting that a third of Antarctica’s emperor penguins could be wiped out by 2100.

The emperor penguin, one of Antarctica's most iconic species. (Image http://www.emperor-penguin.com).

The emperor penguin, one of Antarctica’s most iconic species. (image http://www.emperor-penguin.com).

What’s the problem? A predicted loss of sea ice means a loss of krill, the main food source for emperor penguins. Young krill need sea ice to survive as they eat algae that lives in it.

Tasty tasty krill (image National Geographic)

Tasty tasty krill (image National Geographic).

I thought sea ice was increasing in Antarctica? That may well be the case for now, and the study does suggest that penguin numbers may actually increase for a while, but eventually a decline in sea ice will cause a  fall in penguin numbers much steeper than this increase. Can anything be done? The study’s authors suggest that putting in marine protection zones to prevent fishing in areas where penguins need to hunt for food may help, but they don’t expect that penguins will have much ability to adapt to changing conditions, unlike these clever climbing penguins.

Global number of breeding pairs of emperor penguins from 2009 to 2100. (Jenouvrier et al. 2014, Nature Climate Change)

Global number of breeding pairs of emperor penguins from 2009 to 2100. After a short spell of increase the population plummets. (Jenouvrier et al. 2014, Nature Climate Change)

You can read the full study here: http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2280.html
Sammie Buzzard

Book Review- Cupcake Magic by Kate Shirazi

P1070689

£7.99- Pavilion

My rating: 8.5/10

Simple and different cakes that anyone could manage.

I buy most of my baking books on recommendation so I thought it might be useful to start posting some reviews on here. I didn’t want to start with anything negative so here is one of my favorites. It’s subtitled ‘little cakes with attitude’ and I wouldn’t argue with that.

Straight forward instructions and plenty of pictures.

Straight forward instructions and plenty of pictures.

The book is divided into low-faff, medium-faff and high-faff so you know what you’re getting but the really nice thing is even the high-faff recipes look acheivable an really not an extreme amount of effort. The pictures don’t all look like the finely decorated immaculate cupcakes you get in many books: they’re beautiful but not unrealistically perfect and that’s what I really like about this book- they look like they’ve been made by a real person and are something that you could realistically copy (maybe not quite as well but at least you’ll get something that’s reasonably like what you expect!). In terms of ingredients and equipment I’d say they’re all pretty low-faff. Lovely.

Things anyone can do…almost.

The flavorings are great and different without being too wacky (although I’ve not investigate the savory cupcakes section yet)- the ‘grown-up’ mocha cakes have become one of my standard bakes and always disappear even when I worked in a office full of weight watchers fiends.

The best thing is this feels like a book written by a real person. Not a company or team. Kate’s sense of humor comes through and her section about free-range eggs and gluten free cakes just makes you like her. I was recommended this by someone who had attended her cupcake classes and I’m sad that I no longer live in Devon and can’t go. Her website is here, I’d recommend a look, just avoid the wedding cakes, they look too good and will make you sad (unless you’re actually getting married in which case GO, GO NOW).

Tip: This book can be found online for just over a fiver but I picked it up in The Works for about £3- definitely a bargain at that price.

 

My attempt at the star cupcakes. Not the neatest but still not unhappy as was my first time piping with royal icing. My main niggle is the fact that they are stars. Who can even draw a star well let alone pipe one?? Even so, tip in the book of practicing before putting them on the cake was a very good idea.

My attempt at the star cupcakes. Not the neatest but still not unhappy as was my first time piping with royal icing. My main niggle is the fact that they are stars. Come on Kate, who can even draw a star well let alone pipe one?? Even so, the tip in the book of practicing before putting them on the cake was a very good idea.

The Arctic in the news- Arctic sea-ice melt prediction using melt ponds

Even though I’ve mostly stuck to Antarctica news so far this bit is important for two reasons. One it’s about melt ponds, which is what I look at but on the other side of the world, and two it’s the group that I’m part of at Reading, go CPOM!

Melt ponds on Arctic sea ice, copyright NASA Goddard Space Flight Center

Melt ponds on Arctic sea ice, copyright NASA Goddard Space Flight Center

What’s happened?

The CPOM group at Reading have just released a prediction for the 2014 Arctic sea ice minimum. They did this by using the fact that there is a correlation between the fraction of sea ice covered by melt ponds  (pools of melted ice) in spring and the minimum amount of ice that will then be present at the end of the summer.

The reason for this is to do with the ponds being darker than the surrounding ice, as you can see in the image above. This means that they absorb more energy from the sun, which can lead to warming and further melting.

What does this mean?

These short term predictions are mostly important for predicting shipping routes but the more we know about modelling processes such as the formation of these ponds the better models will be for predicting future extents- one of the greatest uncertainties in predicting future global temperature changes is sea ice level fluctuations.

What’s next?

The prediction has been entered into the Arctic Research Consortium of the United States (ARCUS) Sea Ice Prediction Network-  an annual comparison between different scientists’ predictions, but we’ll have to wait until September to see if Reading’s efforts will do well in the rankings!

An inforgraphic produced by University of Reading to go with today's news.

An infographic produced by University of Reading to go with today’s news.

 

 

 

Penguins are going climbing to adapt to climate change!

An emperor penguin (image Photo Volcania)

Until recently it was thought that all emperor penguins bread on fast ice, that’s sea ice attached to the land; much easier to navigate than the cliffs of ice shelves (image Photo Volcania).

It has been well publicised recently that despite sea ice in the Arctic decreasing, sea ice in the Antarctic has been on the increase. Emperor penguins breed on sea ice, so surely this would be a good thing for the penguins?

Unfortunately, this isn’t the case- even though there is more ice forming it’s forming too late for the penguins’ breeding season. The climate of Antarctica is changing, it has warmed more than 5 times the global average over the last century. It is thought that one of the colonies discovered moved as a result of the late arrival of the sea ice, potentially due to a changing climate.

Penguin colonies can actually be spotted in satellite images such as the one below and it was a combination of this and aerial views from planes that alerted scientist to the fact that these colonies that have moved onto ice shelves.

A satellite image of an emperor penguin colony on an ice shelf (Image BAS/Digital Global).

A satellite image of an emperor penguin colony on an ice shelf (Image BAS/Digital Global). Guano is a term for penguin excrement.

It’s not known quite how the penguins manage to climb up cliffs onto the ice shelves as the colonies haven’t been studied up close but it is thought they might be able to shuffle up between ridges formed by draining water on the ice shelves.

Although it is bad news that the penguins are having to do this it’s a nice positive in their chances of future survival. Polar regions warm faster than other areas so this may not be the end of unusual penguin behaviour if the planet continues to warm.

An emperor penguin huddle. The males are left to look after the eggs while the females go off and hunt, they hiddle together to try and survive the freezing conditions such as during the blizzard shown here (image Australian Antarctic Division).

An emperor penguin huddle. The males are left to look after the eggs while the females go off and hunt, they huddle together to try and survive the freezing conditions such as during the blizzard shown here (image Australian Antarctic Division).

 

References:

The original research article (Fretwell et al.) is http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0085285

Rationing Recipes 3- Bakewell Tart

A slice of wartime goodness.

A slice of wartime goodness.

I used to hate bakewell tarts when I was younger. Children’s birthday parties would have these exciting tiny cakes covered with icing and a glace cherry… but take a bite and you get almond flavour, bleugh. Massive disappointment to a five year old. Here there are no cherries so no lies.

This is a rationing version of a British classic. Sweet enough but not too much, sadly no hidden vegetables this time though.

 

Shortcrust pastry:

6oz self raising flour (to use plain and add 1.5 tsp baking powder)
1.5-2oz margarine
Water to mix

Filling:

2 tbsps jam
2oz margarine
2oz sugar
1 tsp almond essence
1 egg
2oz self-raising flour (add 0.5 tsp baking powder if using plain)
2oz breadcrumbs
2oz soya flour*
2 tbsps milk

*I struggled to find this so had to substitute with ground almonds (which I’m told would have been available but limited). The internet suggests it may be in ‘world foods’ or ‘free from’ sections of supermarkets but I had no luck… It may be available in health food shops but I suspect that it’s been replaced with other gluten free alternatives that aren’t GM in mainstream supermarkets.

1. Rub together the margarine and flour to form a consistency like breadcrumbs, then add water until you can make a firm dough. This pastry seemed very dry and crumbly to me (I normally use double the fat) so be careful not to overdo the water and get something too sticky.

2. Line a pie/flan tin with the pastry- it was so crumbly I found it easier to mould it to the tin rather than rolling out first.

3. Spread the jam over the pastry.

4. Cream together the butter, sugar and almond essence. Beat in the egg.

5. Fold in the flour and stir in the breadcrumbs, soya flour and milk.

6. Cook for 40 mins at 180 degrees centigrade or Gas Mark 4.

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