Antarctica has lost 3 trillion tonnes of ice in 25 years. Time is running out for the frozen continent



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As the world prevaricates over climate action, Antarctica’s future is shrouded in uncertainty.
Hamish Pritchard/British Antarctic Survey

Steve Rintoul, CSIRO and Steven Chown, Monash University

Antarctica lost 3 trillion tonnes of ice between 1992 and 2017, according to a new analysis of satellite observations. In vulnerable West Antarctica, the annual rate of ice loss has tripled during that period, reaching 159 billion tonnes a year. Overall, enough ice has been lost from Antarctica over the past quarter-century to raise global seas by 8 millimetres.

What will Antarctica look like in the year 2070, and how will changes in Antarctica impact the rest of the globe? The answer to these questions depends on choices we make in the next decade, as outlined in our accompanying paper, also published today in Nature.




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Ocean waves and lack of sea ice can trigger Antarctic ice shelves to disintegrate


Our research contrasts two potential narratives for Antarctica over the coming half-century – a story that will play out within the lifetimes of today’s children and young adults.

While the two scenarios are necessarily speculative, two things are certain. The first is that once significant changes occur in Antarctica, we are committed to centuries of further, irreversible change on global scales. The second is that we don’t have much time – the narrative that eventually plays out will depend on choices made in the coming decade.

Change in Antarctica has global impacts

Despite being the most remote region on Earth, changes in Antarctica and the Southern Ocean will have global consequences for the planet and humanity.

For example, the rate of sea-level rise depends on the response of the Antarctic ice sheet to warming of the atmosphere and ocean, while the speed of climate change depends on how much heat and carbon dioxide is taken up by the Southern Ocean. What’s more, marine ecosystems all over the world are sustained by the nutrients exported from the Southern Ocean to lower latitudes.

From a political perspective, Antarctica and the Southern Ocean are among the largest shared spaces on Earth, regulated by a unique governance regime known as the Antarctic Treaty System. So far this regime has been successful at managing the environment and avoiding discord.

However, just as the physical and biological systems of Antarctica face challenges from rapid environmental change driven by human activities, so too does the management of the continent.

Antarctica in 2070

We considered two narratives of the next 50 years for Antarctica, each describing a plausible future based on the latest science.

In the first scenario, global greenhouse gas emissions remain unchecked, the climate continues to warm, and little policy action is taken to respond to environmental factors and human activities that affect the Antarctic.

Under this scenario, Antarctica and the Southern Ocean undergo widespread and rapid change, with global consequences. Warming of the ocean and atmosphere result in dramatic loss of major ice shelves. This causes increased loss of ice from the Antarctic ice sheet and acceleration of sea-level rise to rates not seen since the end of the last glacial period more than 10,000 years ago.

Warming, sea-ice retreat and ocean acidification significantly change marine ecosystems. And unrestricted growth in human use of Antarctica degrades the environment and results in the establishment of invasive species.

Under the high-emissions scenario, widespread changes occur by 2070 in Antarctica and the Southern Ocean, with global impacts.
Rintoul et al. 2018. Click image to enlarge.

In the second scenario, ambitious action is taken to limit greenhouse gas emissions and to establish policies that reduce human pressure on Antarctica’s environment.

Under this scenario, Antarctica in 2070 looks much like it does today. The ice shelves remain largely intact, reducing loss of ice from the Antarctic ice sheet and therefore limiting sea-level rise.

An increasingly collaborative and effective governance regime helps to alleviate human pressures on Antarctica and the Southern Ocean. Marine ecosystems remain largely intact as warming and acidification are held in check. On land, biological invasions remain rare. Antarctica’s unique invertebrates and microbes continue to flourish.

Antarctica and the Southern Ocean in 2070, under the low-emissions (left) and high-emissions (right) scenarios. Each of these systems will continue to change after 2070, with the magnitude of the change to which we are committed being generally much larger than the change realised by 2070.
Rintoul et al. 2018. Click image to enlarge.

The choice is ours

We can choose which of these trajectories we follow over the coming half-century. But the window of opportunity is closing fast.

Global warming is determined by global greenhouse emissions, which continue to grow. This will commit us to further unavoidable climate impacts, some of which will take decades or centuries to play out. Greenhouse gas emissions must peak and start falling within the coming decade if our second narrative is to stand a chance of coming true.

If our more optimistic scenario for Antarctica plays out, there is a good chance that the continent’s buttressing ice shelves will survive and that Antarctica’s contribution to sea-level rise will remain below 1 metre. A rise of 1m or more would displace millions of people and cause substantial economic hardship.

Under the more damaging of our potential scenarios, many Antarctic ice shelves will likely be lost and the Antarctic ice sheet will contribute as much as 3m of sea level rise by 2300, with an irreversible commitment of 5-15m in the coming millennia.

The ConversationWhile challenging, we can take action now to prevent Antarctica and the world from suffering out-of-control climate consequences. Success will demonstrate the power of peaceful international collaboration and show that, when it comes to the crunch, we can use scientific evidence to take decisions that are in our long-term best interest.

The choice is ours.

Steve Rintoul, Research Team Leader, Marine & Atmospheric Research, CSIRO and Steven Chown, Professor of Biological Sciences, Monash University

This article was originally published on The Conversation. Read the original article.

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Are solar panels a middle-class purchase? This survey says yes


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The latest research suggests that in Australia, rooftop solar photovoltaics are more likely to be adopted by middle-class households.
Author provided

Adam McHugh, Murdoch University

The rate of growth in residential rooftop solar photovoltaics (PV) in Australia since 2008 has been nothing short of breathtaking.

Our new research suggests that the households most likely to join in the solar spree are those that are affluent enough to afford the upfront investment, but not so wealthy that they don’t worry about their future power bills.

Australia now has the highest penetration of residential rooftop PV of any country in the world, with the technology having been installed on one in five freestanding or semi-detached homes. In the market-leading states of Queensland and South Australia this ratio is about one in three, and Western Australia is not far behind, with one in four having PV.

The explosion in rooftop PV uptake since 2008.
Derived from Clean Energy Regulator data. Click image to enlarge.

While PV panels give households more control over their electricity bills, and each new installation helps reduce greenhouse gas emissions, the market’s rapid expansion has posed significant challenges for the management of the electricity system as a whole.




Read more:
The electricity network is changing fast, here’s where we’re heading


Unlike other industries where goods can be warehoused or stockpiled to manage fluctuations in supply and demand, electricity is not yet readily storable. Storage options such as batteries are now commercially available, but haven’t yet reached widespread use. This means that a system operator is required to keep the grid balanced in real time, ideally with just the right amount of capacity and backup to manage shocks in supply or demand.

Securing the right amount of generation capacity for the electricity grid relies on long-term planning, informed by accurate supply and demand forecasts. Too much investment means excessive prices or assets lying idle (or both). Too little means longer, deeper or more frequent blackouts.

But as solar panels spread rapidly through the suburbs, the job of forecasting supply and demand is getting much harder.

This is because the commercial history of residential rooftop PV has been too short, and the pace of change too fast, for a clear uptake trend to be established. Previous attempts to predict the market’s continuing growth have thus entailed a lot of guesswork.

Why do people buy solar panels?

One way to improve our understanding is to talk to consumers directly about their purchasing intentions and decisions. The trick is to find out what prompts householders to take that final step from considering investing in solar panels, to actually buying them.

This was the approach we took with our research, published today in the international journal, Renewable and Sustainable Energy Reviews. We analysed data from a survey of more than 8,000 Queensland households in 2014 and 2015, part of a survey series commissioned by an industry group now known as Energy Queensland.

Comparison of motivational factors between surveyed PV intenders and adopters.
Bondio, Shahnazari & McHugh (2018). Click image to enlarge.

We found that the decision to go solar was driven largely by housholds’ concerns over rising electricity bills and the influence that economic life events have over perceptions of affordability.

But the households that tended to adopt PV were also those that were affluent enough not to be put off by the relatively large upfront cost.

This combination of having access to funds, while at the same time being concerned about future electricity prices, appears to be a broadly middle-class trait.

While the upfront cost of PV can deter lower-income households, this can be overcome by receiving an offer that is too good to refuse, or if concerns about ongoing electricity bills are acute – particularly in the case of retirees.

Electricity price uncertainty is a particular concern for retirees, who typically have a lower income. We found that retirees were more likely than non-retirees to invest in solar panels, all else being equal. Retirees, like many people who invest in solar power, seem to view buying solar panels as being like entering into a long-term contract for electricity supply, in that it provides price certainty over the life of the PV system.

We also found that while the idea of self-sufficiency was important for developing an intention to buy solar panels, this motivation later fell away among households that went ahead and bought them. This could be because householders who buy solar panels, but find themselves still relying significantly on the grid, may conclude that self-sufficiency isn’t achievable after all.

About one-third of those who said they intended to buy solar panels cited environmental concerns as a reason for their interest. Yet this factor did not significantly increase the odds of them going on to adopt the technology. This suggests that when it comes to the crunch, household finances are often the crucial determining factor.




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WA bathes in sunshine but the poorest households lack solar panels – that needs to change


We also found the chances of adopting solar panels were highest for homes with three or four bedrooms. Smaller homes may face practical limitations regarding roof space, whereas homes with five bedrooms or more are likely to be more valuable, suggesting that these householders may sit above a wealth threshold beyond which they are unconcerned about electricity bills.

But perhaps our most important finding is that analysis of household survey data can be useful to forecasters. Knowing who is adopting rooftop PV – and why – should enable better predictions to be made about the technology’s continuing expansion, including the crucial question of when the market might reach its saturation point.


The ConversationThe research paper can be downloaded here for free until August 1, 2018.

Adam McHugh, Honorary Research Associate, Murdoch University

This article was originally published on The Conversation. Read the original article.