Arctic ice loss is worrying, but the giant stirring in the South could be even worse



Field camp on the East Antarctic ice sheet.
Nerilie Abram

Nerilie Abram, Australian National University; Matthew England, UNSW, and Matt King, University of Tasmania

A record start to summer ice melt in Greenland this year has drawn attention to the northern ice sheet. We will have to wait to see if 2019 continues to break ice-melt records, but in the rapidly warming Arctic the long-term trends of ice loss are clear.

But what about at the other icy end of the planet?

Antarctica is an icy giant compared to its northern counterpart. The water frozen in the Greenland ice sheet is equivalent to around 7 metres of potential sea level rise. In the Antarctic ice sheet there are around 58 metres of sea-level rise currently locked away.

Like Greenland, the Antarctic ice sheet is losing ice and contributing to unabated global sea level rise. But there are worrying signs Antarctica is changing faster than expected and in places previously thought to be protected from rapid change.

The threat from beneath

On the Antarctic Peninsula – the most northerly part of the Antarctic continent – air temperatures over the past century have risen faster than any other place in the Southern Hemisphere. Summer melting already happens on the Antarctic Peninsula between 25 and 80 days each year. The number of melt days will rise by at least 50% when global warming hits the soon-to-be-reached 1.5℃ limit set out in the Paris Agreement, with some predictions pointing to as much as a 150% increase in melt days.

But the main threat to the Antarctic ice sheet doesn’t come from above. What threatens to truly transform this vast icy continent lies beneath, where warming ocean waters (and the vast heat carrying capacity of seawater) have the potential to melt ice at an unprecedented rate.




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Almost all (around 93%) of the extra heat human activities have caused to accumulate on Earth since the Industrial Revolution lies within the ocean. And a large majority of this has been taken into the depths of the Southern Ocean. It is thought that this effect could delay the start of significant warming over much of Antarctica for a century or more.

However, the Antarctic ice sheet has a weak underbelly. In some places the ice sheet sits on ground that is below sea level. This puts the ice sheet in direct contact with warm ocean waters that are very effective at melting ice and destabilising the ice sheet.

Scientists have long been worried about the potential weakness of ice in West Antarctica because of its deep interface with the ocean. This concern was flagged in the first report of the Intergovernmental Panel on Climate Change (IPCC) way back in 1990, although it was also thought that substantial ice loss from Antarctica wouldn’t be seen this century. Since 1992 satellites have been monitoring the status of the Antarctic ice sheet and we now know that not only is ice loss already underway, it is also vanishing at an accelerating rate.

The latest estimates indicate that 25% of the West Antarctic ice sheet is now unstable, and that Antarctic ice loss has increased five-fold over the past 25 years. These are remarkable numbers, bearing in mind that more than 4 metres of global sea-level rise are locked up in the West Antarctic alone.

Antarctic ice loss 1992–2019, European Space Agency.




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Antarctica has lost nearly 3 trillion tonnes of ice since 1992


Thwaites Glacier in West Antarctica is currently the focus of a major US-UK research program as there is still a lot we don’t understand about how quickly ice will be lost here in the future. For example, gradual lifting of the bedrock as it responds to the lighter weight of ice (known as rebounding) could reduce contact between the ice sheet and warm ocean water and help to stabilise runaway ice loss.

On the other hand, melt water from the ice sheets is changing the structure and circulation of the Southern Ocean in a way that could bring even warmer water into contact with the base of the ice sheet, further amplifying ice loss.

There are other parts of the Antarctic ice sheet that haven’t had this same intensive research, but which appear to now be stirring. The Totten Glacier, close to Australia’s Casey station, is one area unexpectedly losing ice. There is a very pressing need to understand the vulnerabilities here and in other remote parts of the East Antarctic coast.

The other type of ice

Sea ice forms and floats on the surface of the polar oceans. The decline of Arctic sea ice over the past 40 years is one of the most visible climate change impacts on Earth. But recent years have shown us that the behaviour of Antarctic sea ice is stranger and potentially more volatile.

The extent of sea ice around Antarctica has been gradually increasing for decades. This is contrary to expectations from climate simulations, and has been attributed to changes in the ocean structure and changing winds circling the Antarctic continent.

But in 2015, the amount of sea ice around Antarctica began to drop precipitously. In just 3 years Antarctica lost the same amount of sea ice the Arctic lost in 30.




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So far in 2019, sea ice around Antarctica is tracking near or below the lowest levels on record from 40 years of satellite monitoring. In the long-term this trend is expected to continue, but such a dramatic drop over only a few years was not anticipated.

There is still a lot to learn about how quickly Antarctica will respond to climate change. But there are very clear signs that the icy giant is awakening and – via global sea level rise – coming to pay us all a visit.The Conversation

Nerilie Abram, ARC Future Fellow, Research School of Earth Sciences; Chief Investigator for the ARC Centre of Excellence for Climate Extremes, Australian National University; Matthew England, Australian Research Council Laureate Fellow; Deputy Director of the Climate Change Research Centre (CCRC); Chief Investigator in the ARC Centre of Excellence in Climate System Science, UNSW, and Matt King, Professor, Surveying & Spatial Sciences, School of Technology, Environments and Design, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Global Warming and Antarctica


Rising seas threaten Australia’s major airports – and it may be happening faster than we think



Sydney’s airport is one of the most vulnerable in Australia to sea level rise.
Shutterstock

Thomas Mortlock, Macquarie University; Andrew Gissing, Macquarie University; Ian Goodwin, Macquarie University, and Mingzhu Wang

Most major airports in Australia are located on reclaimed swamps, sitting only a few metres above the present day sea level. And the risk of sea level rise from climate change poses a greater threat to our airports than we’re prepared for.

In fact, some of the top climate scientists now believe global sea-level rise of over two metres by 2100 is likely under our current trajectory of high carbon emissions.




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This makes Cairns (less than 3m above sea level), Sydney and Brisbane (under 4m), and Townsville and Hobart (both around under 5m) airports among the most vulnerable.

Antarctica’s ice sheets could be melting faster than we think.
Tanya Patrick/CSIRO science image, CC BY

In the US, the National Oceanic and Atmospheric Administration (NOAA) has recommended that global mean sea level rise of up to 2.7 metres this century should be considered in planning for coastal infrastructure.

This is two to three times greater than the upper limit of recommended sea level rise projections applied in Australia.

But generally, the amount of sea level rise we can expect over the coming century is deeply uncertain. This is because ice sheet retreat rates from global warming are unpredictable.




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Given the significant disruption cost and deep uncertainty associated with the timing of sea level rise, we must adopt a risk-based approach which considers extreme sea level rise scenarios as part of coastal infrastructure planning.

Are we prepared?

As polar ocean waters warm, they can cause glaciers to melt from beneath, leading to more icebergs breaking off into the ocean and then a rapid rise in global sea level. This has happened multiple times in the Earth’s past and, on some occasions, in a matter of decades.

The Intergovernmental Panel on Climate Change (IPCC) puts sea level rise projections for Australia somewhere between 50 to 90 centimetres by 2090, relative to the average sea level measured between 1986 to 2005. But the emerging science indicates this may now be an underestimate.

Some studies suggest if substantive glacial basins of the West Antarctic Ice Sheet were to collapse, it could contribute at least a further two metres to global sea levels.

Most Australian airports have conducted risk assessments for the IPCC projections.

In fact, there is no state-level policy that considers extreme sea level rise for the most critical infrastructure, even though it is possible sea levels could exceed those recommended by the IPCC within the coming century.




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And for airports, the planning implications are stark when you compare the current projection of less than a metre of sea level rise and the potential of at least a two metre rise later this century.

Taking the most low-lying major airports in Australia as an example, our modelling suggests a collapse of the West Antarctic Ice Sheet would see their near complete inundation – without any adaptation in place.

For more elevated locations, coastal infrastructure may still be inoperable more frequently when the combined effect of storm surges, waves, elevated groundwater or river flooding are considered.

A $200 billion problem

Our airports and other forms of infrastructure near the coastline are critical to the Australian economy. The aviation industry has an estimated annual revenue of over A$43 billion, adding around A$16 billion to the economy in 2017.

While there are many uncertainties around the future cost of sea-level rise, a study by the Climate Council suggests over a metre sea level rise would put more than A$200 billion worth of Australian infrastructure at risk.

It is difficult to assign a probability and time-frame to ice sheet collapse, but scientific estimates are reducing that time frame to a century rather than a millennium.




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Uncertainty generally comes with a cost, so proactive planning would make economic sense.

Adapting our most critical coastal assets while sea levels rapidly rise is not an option – mitigation infrastructure could take decades to construct and may be prohibitively expensive.

Given the deep uncertainties associated with the timing of ice-sheet collapse, we suggest airport and other critical coastal infrastructure is subjected to risk analysis for a two to three metre sea level rise.The Conversation

Thomas Mortlock, Senior Risk Scientist, Risk Frontiers, Adjunct Fellow, Macquarie University; Andrew Gissing, General Manager, Risk Frontiers, Adjunct Fellow, Macquarie University; Ian Goodwin, Associate Professor, Macquarie University, and Mingzhu Wang, Senior Geospatial Scientist, Risk Frontiers, Adjunct Fellow, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate change forced these Fijian communities to move – and with 80 more at risk, here’s what they learned


File 20190430 136787 bz9zdf.jpg?ixlib=rb 1.1
Many houses were flattened after Tropical Cyclone Evan, leading to the partial relocation of the Fijian viillage Denimanu.
Rowena Harbridge/AusAID, CC BY-SA

Annah Piggott-McKellar, The University of Queensland; Karen Elizabeth McNamara, The University of Queensland, and Patrick D. Nunn, University of the Sunshine Coast

The original Fijian village of Vunidogoloa is abandoned. Houses, now dilapidated, remain overgrown with vegetation. Remnants of an old seawall built to protect the village is a stark reminder of what climate change can do to a community’s home.

Vunidogoloa is one of four Fijian communities that have been forced to relocate from the effects of climate change. And more than 80 communities have been earmarked by the Fiji government for potential future relocation.




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Low lying coastal communities like these are especially vulnerable to threats of sea-level rise, inundation of tides, increased intensity of storm surges and coastal erosion. Extreme, sudden weather events such as cyclones can also force communities to move, particularly in the tropics.

But relocating communities involves much more than simply rebuilding houses in a safer location.

It involves providing the right conditions for people to rebuild the lives they knew, such as equitable access to resources and services, social capital and community infrastructure.

Our research documents the experiences and outcomes of relocation for two of these Fijian communities – Vunidogoloa and Denimanu.

The relocated villages

My colleagues and I visited Vunidogoloa and Denimanu, villages in Fiji’s Northern Islands, at the end of 2017 and spoke to village leaders and community members to learn how they felt about the relocation process.

All 153 residents of Vunidogoloa and roughly half of the 170 people in Denimanu moved away from their climate ravaged homes.

Map of Fiji showing the two case study sites.
Author provided

Flooding in Vunidogoloa

Vunidogoloa is a classic example of the slow creep of climate change. For a number of decades the residents have fought coastal flooding, salt-water intrusion and shoreline erosion. The village leaders approached the Fijian government, asking to be relocated to safer ground.

The relocation was originally set for 2012 but, after delays, the entire village moved roughly 1.5 kilometres inland two years later. This is often recognised as the first ever village in Fiji to relocate from climate change.

The new village relocation site of Vunidogoloa.

Cyclone in Denimanu

In contrast to Vunidogoloa, Denimanu experienced sudden onset effects of climate change.

While the village had been experiencing encroaching shorelines for years, it was Tropical Cyclone Evan, which hit in 2012 destroying 19 houses closest to the shoreline, that prompted relocation.




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These homes were rebuilt roughly 500 metres from the original site on a hill slope. With the remaining houses still standing on the original site, the village was only partially moved.

The new village relocation site of Denimanu.
Author provided

Was relocation a success?

The relocation was a success in Vunidogoloa, and residents said they now feel much safer from climate change hazards. One villager told us:

We were so fearful because of the tides living at the old site. We were happy to move away from that fear.

But in Denimanu, where the relocated villagers live on a slope, fears of coastal threats have now been replaced by a fear of potential landslides. This is especially concerning as the village’s primary school was recently destroyed by a nearby landslide.

A relocated Denimanu local said:

We were delighted with the move to the new houses, but we were still worried about the landslide because the houses were on the hill and we know this place.

The landslide that destroyed the primary school in Denimanu village.

Ultimately, residents in both villages were happy with many aspects of the relocation process.

For example, they were provided solar power, rainwater tanks, and household facilities that weren’t available in the original villages. Vunidogoloa also received pineapple plants, cattle, and fish ponds, which have helped reestablish their livelihoods.

But it’s not all good news. While new housing was built for the community, they were built to a poor standard, with leaking through the doors and walls, especially in periods of high rainfall. Fiji is located in the tropics, so these infrastructure problems are likely to get worse.




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And moving the Vunidogoloa villagers away from the ocean might damage their livelihoods, as fishing is one of their dominant sources of food. The ocean also provides an important spiritual connection for local people.

The impacts of climate change are set to rise, especially if global action to halt greenhouse gas emissions stagnates. More vulnerable communities will need to move away from their current homes.

While relocating communities to safer, less exposed areas is one option to help people manage climate hazards, it’s not a viable solution for all those affected.

Our research shows relocation must be done in a manner that accounts for the rebuilding of local livelihoods, with sustainable adaptation solutions that put local priorities at the centre of this process.

And we need them before more coastal villages are impacted by both slow and sudden onset climate impacts, putting more people in danger.The Conversation

Annah Piggott-McKellar, PhD Candidate, The University of Queensland; Karen Elizabeth McNamara, Senior lecturer, The University of Queensland, and Patrick D. Nunn, Professor of Geography, School of Social Sciences, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Rising seas allow coastal wetlands to store more carbon



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Carbon storage in Australian mangroves can help mitigate climate change.
Shutterstock

Kerrylee Rogers, University of Wollongong; Jeffrey Kelleway, Macquarie University, and Neil Saintilan, Macquarie University

Coastal wetlands don’t cover much global area but they punch well above their carbon weight by sequestering the most atmospheric carbon dioxide of all natural ecosystems.

Termed “blue carbon ecosystems” by virtue of their connection to the sea, the salty, oxygen-depleted soils in which wetlands grow are ideal for burying and storing organic carbon.

In our research, published today in Nature, we found that carbon storage by coastal wetlands is linked to sea-level rise. Our findings suggest as sea levels rise, these wetlands can help mitigate climate change.

Sea-level rise benefits coastal wetlands

We looked at how changing sea levels over the past few millennia has affected coastal wetlands (mostly mangroves and saltmarshes). We found they adapt to rising sea levels by increasing the height of their soil layers, capturing mineral sediment and accumulating dense root material. Much of this is carbon-rich material, which means rising sea levels prompt the wetlands to store even more carbon.

We investigated how saltmarshes have responded to variations in “relative sea level” over the past few millennia. (Relative sea level is the position of the water’s edge in relation to the land rather than the total volume of water within the ocean, which is called the eustatic sea level.)




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What does past sea-level rise tell us?

Global variation in the rate of sea-level rise over the past 6,000 years is largely related to the proximity of coastlines to ice sheets that extended over high northern latitudes during the last glacial period, some 26,000 years ago.

As ice sheets melted, northern continents slowly adjusted elevation in relation to the ocean due to flexure of the Earth’s mantle.

Karaaf Wetlands in Victoria, Australia.
Boobook48/flickr, CC BY-NC-SA

For much of North America and Europe, this has resulted in a gradual rise in relative sea level over the past few thousand years. By contrast, the southern continents of Australia, South America and Africa were less affected by glacial ice sheets, and sea-level history on these coastlines more closely reflects ocean surface “eustatic” trends, which stabilised over this period.

Our analysis of carbon stored in more than 300 saltmarshes across six continents showed that coastlines subject to consistent relative sea-level rise over the past 6,000 years had, on average, two to four times more carbon in the upper 20cm of sediment, and five to nine times more carbon in the lower 50-100cm of sediment, compared with saltmarshes on coastlines where sea level was more stable over the same period.

In other words, on coastlines where sea level is rising, organic carbon is more efficiently buried as the wetland grows and carbon is stored safely below the surface.

Give wetlands more space

We propose that the difference in saltmarsh carbon storage in wetlands of the southern hemisphere and the North Atlantic is related to “accommodation space”: the space available for a wetland to store mineral and organic sediments.

Coastal wetlands live within the upper portion of the intertidal zone, roughly between mean sea level and the upper limit of high tide.

These tidal boundaries define where coastal wetlands can store mineral and organic material. As mineral and organic material accumulates within this zone it creates layers, raising the ground of the wetlands.

The coastal wetlands of Broome, Western Australia.
Shutterstock

New accommodation space for storage of carbon is therefore created when the sea is rising, as has happened on many shorelines of the North Atlantic Ocean over the past 6,000 years.

To confirm this theory we analysed changes in carbon storage within a unique wetland that has experienced rapid relative sea-level rise over the past 30 years.




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When underground mine supports were removed from a coal mine under Lake Macquarie in southeastern Australia in the 1980s, the shoreline subsided a metre in a matter of months, causing a relative rise in sea level.

Following this the rate of mineral accumulation doubled, and the rate of organic accumulation increased fourfold, with much of the organic material being carbon. The result suggests that sea-level rise over the coming decades might transform our relatively low-carbon southern hemisphere marshes into carbon sequestration hot-spots.

How to help coastal wetlands

The coastlines of Africa, Australia, China and South America, where stable sea levels over the past few millennia have constrained accommodation space, contain about half of the world’s saltmarshes.

Saltmarsh on the shores of Westernport Bay in Victoria.
Author provided

A doubling of carbon sequestration in these wetlands, we’ve estimated, could remove an extra 5 million tonnes of CO₂ from the atmosphere per year. However, this potential benefit is compromised by the ongoing clearance and reclamation of these wetlands.

Preserving coastal wetlands is critical. Some coastal areas around the world have been cut off from tides to lessen floods, but restoring this connection will promote coastal wetlands – which also reduce the effects of floods – and carbon capture, as well as increase biodiversity and fisheries production.




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In some cases, planning for future wetland expansion will mean restricting coastal developments, however these decisions will provide returns in terms of avoided nuisance flooding as the sea rises.

Finally, the increased carbon storage will help mitigate climate change. Wetlands store flood water, buffer the coast from storms, cycle nutrients through the ecosystem and provided vital sea and land habitat. They are precious, and worth protecting.


The authors would like to acknowledge the contribution of their colleagues, Janine Adams, Lisa Schile-Beers and Colin Woodroffe.The Conversation

Kerrylee Rogers, Associate Professor, University of Wollongong; Jeffrey Kelleway, Postdoctoral Research Fellow in Environmental Sciences, Macquarie University, and Neil Saintilan, Head, Department of Environmental Science, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

For Pacific Island nations, rising sea levels are a bigger security concern than rising Chinese influence



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Malcolm Turnbull promised to ‘step up’ Australian engagement with the Pacific last year. Will it continue now that he’s gone?
Lukas Coch/AAP

Michael O’Keefe, La Trobe University

When the Pacific Islands Forum is held in Nauru from September 1, one of the main objectives will be signing a wide-ranging security agreement that covers everything from defence and law and order concerns to humanitarian assistance and disaster relief.

The key question heading into the forum is: can the agreement find a balance between the security priorities of Australia and New Zealand and the needs of the Pacific Island nations?

Even though new Prime Minister Scott Morrison is not attending the forum, sending Foreign Minister Marise Payne instead, the Biketawa Plus security agreement remains a key aim for Canberra.




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The original Biketawa Declaration was developed as a response to the 2000 coup in Fiji. It has served Australia and the region well, providing a framework for collective action when political tensions and crises occur. However, in the face of rapid change, it looks narrow and dated.

Why act now? The rationale is clear. Much has happened to alter the security landscape in the Pacific since 2000. But despite the commentary in Australia, security in the Pacific is not all about geopolitics. While Australia may be most worried about China’s rising influence in the region, it would be a mistake to think this is the primary preoccupation of Pacific leaders, too.

A focus on climate change as a security issue

One key reason for updating Biketawa is to realign Australia’s security interests with those of Pacific Island countries that have grown more aware of their shared interests and confident in expressing them in international relations. This growing confidence is clear in the lobbying of Pacific nations for climate change action at the United Nations and in Fiji’s role as president of the UN’s COP23 climate talks.

In the absence of direct military threats, the Pacific Island nations are most concerned about security of a different kind. Key issues for the region are sustainable growth along a “blue-green” model, climate change (especially the increasing frequency and intensity of natural disasters and rising sea levels), illegal fishing and over-fishing, non-communicable diseases (NCDs), transnational crime, money laundering and human trafficking.




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Some of these security issues can be addressed by redirecting more Australian military forces to the region. Indeed, “disaster diplomacy” has been an effective method of connecting Australia’s security interests with those of Pacific Island nations in the past.

However, other priorities for the Pacific seem to run counter to Australia’s current policies toward the region. For example, the Pacific’s sustainable “blue-green” development agenda seems incompatible with an export-oriented growth model that is often touted by Australia as an “aid for trade” solution to Pacific “problems”.

Climate change adaptation and mitigation must also be elevated to the top of the agenda in Australia’s relations with the region. It is the most pressing problem in the Pacific, but for political and economic reasons, it hasn’t resonated to the same extent with Canberra.

In fact, Australia has recently been identified as the worst-performing country in the world on climate action. This has not gone unnoticed in the Pacific. Fiji’s prime minister, in particular, has been clear in highlighting that Australia’s “selfish” stance on climate change undermines its credibility in the region.

These shifting priorities in the Pacific present a greater challenge for Australia, especially now that there are more players in the region, such as China, Russia and Indonesia. Australia may see these “outsiders” as potential threats, but Pacific nations are just as likely to view them as alternative development partners able to provide opportunities.

New Coalition team on the Pacific

Making matters even trickier is the leadership shake-up in Canberra. What’s perhaps most problematic is Julie Bishop’s departure as foreign minister. Bishop did more to engage with Pacific countries than any foreign minister in recent memory. The [2017 Foreign Policy White Paper], for example, prioritised increased Pacific engagement and led to the region receiving the lion’s share of Australia’s latest aid budget.

Payne will attend the Pacific Islands Forum on her first overseas visit as foreign minister. As the former defence minister, she lobbied for Australia to be seen as a “security partner of choice” in the Pacific. What remains to be seen is whether she can maintain the momentum on Biketawa Plus.




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So the challenge for the new Coalition leadership is to find a way to push through a new Pacific security agreement that caters to both Australia’s security concerns about Chinese influence in the region and the Pacific Island countries’ focus on climate change and sustainable growth.

There are lessons that can be drawn from the decade-long negotiations between Australia, New Zealand and the Pacific Island nations over the Pacer Plus free-trade agreement, which was finally signed last year (without the region’s two largest economies, Papua New Guinea and Fiji). Australia must not underestimate the diplomatic skills of Pacific leaders or offer benefits that are perceived as being more attractive to it than the Pacific states.

Australia must also avoid allowing the leadership spill to impact its Pacific agenda at this sensitive time. Bishop’s focus on labour mobility between the Pacific islands and Australia has been most welcome, but there can be no authentic engagement with the region without addressing climate insecurity as well.The Conversation

Michael O’Keefe, Head of Department, Politics and Philosophy, La Trobe University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Rising seas will displace millions of people – and Australia must be ready


Jane McAdam, UNSW and John Church, UNSW

Sea-level rise is already threatening some communities around the world, particularly small island states, as it exacerbates disasters resulting from storm surges and flooding.

If greenhouse gas emissions continue unabated, by 2100 the world could see sea-level rise of a metre – or even more if there is a larger contribution from the Antarctic ice sheet, as some recent findings suggest.

Even without a larger Antarctic response, the rate of rise at the end of the 21st century for unmitigated emissions is likely to be equivalent to the rate of rise during the last deglaciation of the Earth, when sea level rose at more than a metre per century for many millennia. For all scenarios, sea-level rise will continue for centuries to come.




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Without significantly more effective mitigation than currently planned, the rise will ultimately be many metres, or even tens of metres – the question is not if there will be large rises, but how quickly they will happen.

Forcing people from their homes

As well as causing seas to rise, climate change may also increase the severity of events like cyclones and rainfall, which may force people from their homes in many regions.




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Global statistics on the risk of disaster displacement were not systematically collected until 2008, but already they offer stark figures. In 2017, 18.8 million people were internally displaced by natural disasters, with floods accounting for 8.6 million. By contrast, 11.8 million were displaced by conflict. Many more people are displaced each year by disasters than by conflict. Climate change intensifies this risk.

Roughly 100 million people live within about a metre of current high tide level. (Double these numbers for a five-metre sea-level rise, and triple them for 10 metres.)

Many of the world’s megacities are on the coast and vulnerable to sea-level change. Without adaption, it is estimated that by 2100 some of these areas will flood, displacing in the order of 100 million people.

While the vast majority of those people will never cross an international border, some will – and their legal status will be precarious because they will not qualify as refugees under the UN Refugee Convention (people with a well-founded fear of being persecuted for reasons of race, religion, nationality, political opinion or membership of a particular social group).




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In the current political climate, governments are reticent to create a new legal status for such people, and it would be difficult to encapsulate the complexity of climate change and disaster-related movement in a treaty definition anyway. Many factors drive people to leave their homes – such as poverty, resource scarcity and lack of livelihood opportunities – but climate change becomes the straw that breaks the camel’s back.

Good policy is essential

The most effective way to reduce the number of displaced people is strong global mitigation of emissions. In Australia, a successful NEG policy that included emissions reduction would cover about a third of Australia’s emissions. Mitigation policies also need to be developed to cover all emission sectors.

However, even with strong mitigation, adaptation will be essential. The evidence tells us that most people want to remain in their homes for as long as they can, and to return as quickly as possible. We therefore need laws and policies that permit people to remain in their homes where possible and desirable; that enable them to move elsewhere, before disaster strikes, if they wish; and to receive assistance and protection if they are displaced.

Coastal communities could live more effectively with rising sea levels by developing infrastructure, adopting and enforcing appropriate planning and building codes, and controlling flooding to allow sediment deposition. Storm-surge shelters and storm-surge warnings have already saved thousands of lives in countries like Bangladesh.

Good policy is essential. Studies of floods in Bangladesh showed that when people received prompt and adequate assistance, they were more likely to stay and rebuild than to move on in search of work to survive. By contrast, a year after Typhoon Haiyan struck the Philippines, tens of thousands of people remained displaced because the authorities said it was unsafe to go home but could not offer any alternative. This is likely to be a growing challenge with on-going climate change.




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We are going to see more and more climate related disasters. We can do better in the way we prepare for and respond to them. The nature and timing of policy interventions will be crucial in determining outcomes after a disaster, because together they affect people’s ability to cope and be resilient. We need a broad, complementary set of policy strategies to assist people and give them choices.


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The Conversation

On Thursday 24 August Jane McAdam and John Church will join Walter Kaelin to talk on Good Evidence, Bad Politics. This event is free to the public.

Jane McAdam, Scientia Professor and Director of the Kaldor Centre for International Refugee Law, UNSW and John Church, Chair professor, UNSW

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