In the News: Bid for East Antarctic sanctuary fails

A quick Antarctic news update! Last year, at the annual summit of the Commission for the Conservation of Antarctic Marine Living Resources, agreements from all 24 members were secured for a huge marine protected area around the Ross Sea. However, this week the summit failed to reach an agreement for the formation of a similar sanctuary in the East Antarctic, as China and Russia were concerned about compliance and fishing rights.

A marine protected area in the Ross Sea was secured in 2016 (Image: NewsNext)

This is a huge blow for Antarctic wildlife which is threatened by commercial fishing practices and increasingly becoming vulnerable to the effects of climate change. 

Climate Change in The Antarctic Peninsula

With an alpine topography and summer air temperatures frequently above freezing, the Antarctic Peninsula has a very different environment from the rest of the continent. The East Antarctic ice sheet (EAIS) is considerably larger and cooler than the Peninsula, with thicker ice and fewer ice free areas. Temperatures in East Antarctica have shown little change over the last century. 

The Antarctic Peninsula's small size, higher latitude and other environmental factors make it particularly vulnerable to climate change. Between 1950 and 2000 it was reported that surface temperatures increased by 2.5°C and the surrounding oceans warmed. 

The Antarctic Peninsula (Image: NASA)

Wind Matters

The Southern Annual Mode (SAM), is one of the main controllers of climate in Antarctica as it affects the movement of westerlies that circulate the continent. Since the 1960's the SAM has been in its positive phase, resulting in reduced pressures and enhanced westerlies over the Antarctic Peninsula. 

The SAM in its positive phase is characterised by a decrease in pressure over Antarctica (Image: Jones, 2012)

The IPCC has reported that this positive phase has contributed to strong summer warming and reduced sea ice flow in the region.  It has been suggested that this positive shift in the SAM could be partly attributed to  increases in atmospheric greenhouse gases (IPCC, 2007). In fact, Abram et al., 2015 reproduced this positive trend  using multi-model climate simulations coupled with rising greenhouse gases. 

So atmospheric temperatures have risen, oceans have warmed and the SAM has shifted into a positive phase, but what does this mean for the Peninsula?

The Ice is Thinning 

A study by Vaughan et al., 2003 reported that seven major ice shelves were retreating during the second half of the twentieth century over the Antarctic Peninsula; the IPCC has stated that the confidence that this is caused by atmospheric warming is high. In 2002 the collapse of the Larsen B ice shelf made headline news. The break down of this buttressing ice shelf, which acts as a dam to the flow of glaciers into the sea, has been linked to increases in glacial surges. In fact, observations after this event showed that the Hektoria, Green and Evans glaciers accelerated eightfold.

Other glaciers have also been receding:  a study which examined 244 glaciers in the region found that 212 had been retreating, shown on the left in the figure below, and those that had been advancing were doing so at a much slower rate. 

Overall changes in Antarctic Peninsula glacier fronts since 1940. Far more glaciers have retreated (A) than advanced (B) (Image: Cook et al 2005)

The Antarctic Peninsula has unequivocally warmed and according to the IPCC the observed changes to ice shelves and glaciers are irreversible.  Next week I will be examining the evidence of climate change in the East Antarctic Ice Sheet: stay tuned to find out more!

In The News: Only 2 chicks survive from a colony of 18,000 pairs in Antarctica

This week we were met with the terrible news that only 2 Adélie penguin chicks had survived the breeding season, from a colony of 18,000 pairs, in Antarctica earlier this year.  But is this an indicator of climate change or just part of the natural variability in breeding cycles?

Adélie penguins in Antarctica (Image: National Geographic) 

For 45,000 years, populations of Adélie penguins have survived and adapted to the melting and expansion of ice in Antarctica. Today, the penguin colonies' success varies across the southern continent: on the East Antarctic Ice Sheet, numbers have been growing steadily but rapid warming in other areas, particularly across the Antarctic Peninsula, is threatening breeding sites. 

This year, it is believed that the low survival rate of chicks was caused by unusually high amounts of ice which meant adult penguins had to travel much further for their food and leave their chicks for longer. This late sea ice has been attributed to the breakup of the Mertz Glacier in 2010; this glacier had previously helped to keep the nearby ocean ice free. Ice-free areas are known as polynyas. 

Polyn-huh?

Ice-free areas, or coastal polynyas, are maintained by the presence of a topographic or glacial feature (in this case the Mertz Glacier Tongue) and a persistent wind in a singular direction. Simply, this wind drives newly formed sea ice away from the barrier, leaving open water behind it (for a more detailed explanation please follow this link). As Campagne et al., 2015 highlight, the break up of the Mertz Glacier in 2010 disrupted this process: the once ice free area was filled with ice as the important barrier was removed. 

An ice berg (right) collides with the Mertz Glacier tongue in 2010 (Image: Neal Young)

The Future for Adélie Penguins

This catastrophic breeding season may not be linked directly to climate change. However a paper by Cimino et al, 2016 has projected that by 2060 a third of the current colonies will be diminishing. Fishing and tourism, combined with the threats that climate change places on the availability and quality of food, are likely to threaten populations further. Yan Robert-Coudert, who leads the penguin research programme at Durmont D'Urville, recently told The Guardian:

"there may still be years when the breeding will be OK, or even good for this colony, but the scene is set for massive impacts to hit on a more or less regular basis"

Predicted changes in the suitability of breeding sites for Adélie penguins (Image: NASA)

Although this specific event cannot be attributed directly to climate change it highlights the sensitivity of Antarctic species to changing environments. The frequency of such dramatic events is likely to increase with a changing climate and this could threaten the balance of delicate Antarctic ecosystems.

'Ice to meet you

I am studying for an MSc in Climate Change at UCL and it is my own lack of knowledge and awareness about the impacts of climate change in Antarctica that have drawn me to choose it as a topic for this blog series.

Changing Planet 

Throughout the Earth’s history the concentration of carbon dioxide has fluctuated and the average temperature across the globe has varied. However, since the Industrial Revolution, anthropogenic activities have increased greenhouse gases in the atmosphere which has caused global surface temperature increases (across both land and ocean) of 0.85°C between 1880 to 2012. According to the IPCC’s Fifth Assessment Report: 

“Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased”

Global atmospheric concentrations of CO2 over time (Image: EPA) 

The Polar South: Antarctica

The Poles are frequently used as indicators for global climate change: the ice can reveal past changes and assist scientists in modelling the future. The effects of climate change in the Arctic are well documented, and images of polar bears stranded on icebergs a familiar sight on our news. The Antarctic, on the other hand, receives less attention.  

The most southern, and fifth largest, continent is the coldest, driest and windiest on Earth. Comprised of two distinct regions, the West and East, The Antarctic holds roughly 61% of the Earth’s freshwater and is the site of the lowest recorded temperature on Earth, a chilly -89.2°C! 

Emperor Penguins in The Antarctic (Image: National Geographic)

A Complex Picture

Recent temperature changes in The Antarctic are complex, with assessments highlighting spatial heterogeneity. Since the 1950s, monitoring stations have measured some of the fastest warming on Earth across The Antarctic Peninsula, with temperatures rising by 2.5°C between 1950 and 2000 (Turner et al, 2005). The Peninsula’s response? Worryingly, 87% of the glaciers located there are receding, a large part (twice the size of Luxembourg) of the Larcen C ice shelf broke away this summer and melting currently contributes a reported 0.22mm per year to global sea level rise. 

These temperature increases are, to a lesser extent, being recorded across the rest of the West Antarctic Ice Sheet (WAIS) as well.  According to a paper by Steig et al, 2009, warming has exceeded 0.16°C per decade over the past 50 years.

In contrast, the East Antarctic Ice Sheet (EAIS) has experienced little change in temperature and even a slight cooling in places. This means that the mass balance of the ice sheet is in equilibrium or even slightly positive. 

Temperature trends in Antarctica between 1981 and 2007 (Image: NASA Earth Observatory)

Welcome to my Antarctic journey

Over the next few months  I will seek to understand, document and answer the following questions: 

• How is Antarctica responding to a changing climate and what are the spatial complexities?
• How has Antarctica responded to changing climates in the past?
• What does Antarctica's future look like and what are the implications for the rest of the Earth?

So, for now, it was ‘ice to meet you and I hope you will join me on my journey of Antarctic discovery.