Is Malcolm Turnbull the only Liberal who understands economics and climate science – or the only one who’ll talk about it?


Darren England/AAP

Richard Denniss, Crawford School of Public Policy, Australian National UniversityYesterday, former Liberal prime minister Malcolm Turnbull was unceremoniously dumped as chair of the New South Wales government’s climate advisory board, just a week after being offered the role. His crime? He questioned the wisdom of building new coal mines when the existing ones are already floundering.

No-one would suggest building new hotels in Cairns to help that city’s struggling tourism industry. But among modern Liberals it’s patently heresy to ask how rushing to green light 11 proposed coal mines in the Hunter Valley helps the struggling coal industry.

Coal mines in the Hunter are already operating well below capacity and have been laying off workers in the face of declining world demand for coal, plummeting renewable energy prices and trade sanctions imposed by China. The problem isn’t a shortage of supply, but an abundance.

The simple truth is building new coal mines will simply make matters worse, especially for workers in existing coal mines that have already been mothballed or had their output scaled back.

coal mine in the Hunter Valley
Turnbull has called for a moratorium on new coal mines in the Hunter Valley, such as the one pictured above.
Dean Lewins/AAP

It gets worse. Once an enormous, dusty, noisy open cut coal mine is approved, the agriculture, wine, tourism and horse breeding industries – all major employers in the Hunter Valley – are reluctant to invest nearby. While building new coal mines hurts workers in existing coal mines, the mere act of approving new coal mines harms investment in job creation in the industries that offer the Hunter a smooth transition from coal.

The NSW planning department doesn’t have a plan for how many new coal mines are needed to meet world demand. Nor does it have a plan for how much expansion of rail and port infrastructure is required to meet the output of all the new mines being proposed.




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That’s why my colleagues and I recently called for a moratorium on new coal mines in the Hunter until such plans were made explicit. Just as you wouldn’t approve 1,000 new homes in a town where the sewerage system was already at capacity, it makes no sense to approve 11 new coal mines in a region that couldn’t export that much coal if it tried.

But if there’s one thing that defines the debate about coal in Australia, its that it makes no sense.

Just as it made no sense for then-treasurer Scott Morrison to wave a lump of coal around in parliament in 2017, it makes no sense for right-wing commentators to pretend approving new mines will help create jobs in coal mining. And it makes no sense for the National Party to ignore the pleas of farmers to protect their land from the damage coal mines do.

Scott Morrison with a lump of coal to Question Time in 2017.
Scott Morrison took a lump of coal to Question Time in 2017.
Lukas Coch/AAP

On the surface, Turnbull’s support for a pause on approving new mines while a plan is developed is old-fashioned centrism. It protects existing coal workers from new, highly automated mines, it protects farmers and it should make those concerned with climate change at least a bit happy. Win. Win. Win.

But there’s no room for a sensible centre in the Australian coal debate. And when someone even suggests the industry might not be set to grow, its army of loyal parliamentary and media supporters swing into action.

Labor’s Joel Fitzgibbon said Turnbull “wants to make the Upper Hunter a coal-mine-free zone”. The Nationals’ Matt Canavan suggested stopping coal exports was “an inhumane policy to keep people in poverty”. The head of the NSW Minerals Council suggested 12,000 jobs were at risk.

But of course, the opposite is true. Turnbull’s proposal to protect existing coal workers from competition from new mines would save jobs, not threaten them. He didn’t suggest coal mines be shut down tomorrow, or even early. And, given existing coal mines are running so far below capacity, his call has no potential to impact coal exports.




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Coal workers
Opening new coal mines won’t help save the jobs of existing coal workers.
Dan Himbrechts/AAP

Predictably, the Murdoch press ran a relentlessly misleading campaign in support of the coal industry and in opposition to their least favourite Liberal PM. But surprisingly, the NSW government rolled over in record time.

While the government might think appeasing the coal industry will play well among some older regional voters, they must know such kowtowing is a gift to independents such as Zali Steggall, and a fundamental threat to inner-city Liberals such as Dave Sharma, Jason Falinski and Trent Zimmerman.

The decision to dump Turnbull might have bought NSW Premier Gladys Berejiklian some respite from attacks from the Daily Telegraph. But such denial of economics and climate science will provide no respite for existing coal workers in shuttered coal mines or the agriculture and tourism industry that is looking to expand.

No doubt the National Party are pleased with their latest scalp. But it must be remembered this is the party that last year wanted to wage a war against koalas on behalf of property developers. Such political instincts might help the Nationals fend off the threat from One Nation in regional areas but it does nothing to retain votes in leafy Liberal strongholds that deliver most Liberal seats.




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The Conversation


Richard Denniss, Adjunct Professor, Crawford School of Public Policy, Australian National University

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

Marine life is fleeing the equator to cooler waters. History tells us this could trigger a mass extinction event


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Anthony Richardson, The University of Queensland; Chhaya Chaudhary, University of Auckland; David Schoeman, University of the Sunshine Coast, and Mark John Costello, University of AucklandThe tropical water at the equator is renowned for having the richest diversity of marine life on Earth, with vibrant coral reefs and large aggregations of tunas, sea turtles, manta rays and whale sharks. The number of marine species naturally tapers off as you head towards the poles.

Ecologists have assumed this global pattern has remained stable over recent centuries — until now. Our recent study found the ocean around the equator has already become too hot for many species to survive, and that global warming is responsible.

In other words, the global pattern is rapidly changing. And as species flee to cooler water towards the poles, it’s likely to have profound implications for marine ecosystems and human livelihoods. When the same thing happened 252 million years ago, 90% of all marine species died.

The bell curve is warping dangerously

This global pattern — where the number of species starts lower at the poles and peaks at the equator — results in a bell-shaped gradient of species richness. We looked at distribution records for nearly 50,000 marine species collected since 1955 and found a growing dip over time in this bell shape.

A chart with three overlapping lines, each representing different decades. It shows that between 1955 and 1974, the bell curve is almost flat at the top. For the lines 1975-1994 and 1995-2015, the dip gets progressively deeper, with peaks either side of the centre.
If you look at each line in this chart, you can see a slight dip in total species richness between 1955 and 1974. This deepens substantially in the following decades.
Anthony Richardson, Author provided

So, as our oceans warm, species have tracked their preferred temperatures by moving towards the poles. Although the warming at the equator of 0.6℃ over the past 50 years is relatively modest compared with warming at higher latitudes, tropical species have to move further to remain in their thermal niche compared with species elsewhere.

As ocean warming has accelerated over recent decades due to climate change, the dip around at the equator has deepened.

We predicted such a change five years ago using a modelling approach, and now we have observational evidence.




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For each of the 10 major groups of species we studied (including pelagic fish, reef fish and molluscs) that live in the water or on the seafloor, their richness either plateaued or declined slightly at latitudes with mean annual sea-surface temperatures above 20℃.

Today, species richness is greatest in the northern hemisphere in latitudes around 30°N (off southern China and Mexico) and in the south around 20°S (off northern Australia and southern Brazil).

school of tuna fish
The tropical water at the equator is renowned for having the richest diversity of marine life, including large aggregations of tuna fish.
Shutterstock

This has happened before

We shouldn’t be surprised global biodiversity has responded so rapidly to global warming. This has happened before, and with dramatic consequences.

252 million years ago…

At the end of the Permian geological period about 252 million years ago, global temperatures warmed by 10℃ over 30,000-60,000 years as a result of greenhouse gas emissions from volcano eruptions in Siberia.

A 2020 study of the fossils from that time shows the pronounced peak in biodiversity at the equator flattened and spread. During this mammoth rearranging of global biodiversity, 90% of all marine species were killed.

125,000 years ago…

A 2012 study showed that more recently, during the rapid warming around 125,000 years ago, there was a similar swift movement of reef corals away from the tropics, as documented in the fossil record. The result was a pattern similar to the one we describe, although there was no associated mass extinction.

Authors of the study suggested their results might foreshadow the effects of our current global warming, ominously warning there could be mass extinctions in the near future as species move into the subtropics, where they might struggle to compete and adapt.

Today…

During the last ice age, which ended around 15,000 years ago, the richness of forams (a type of hard-shelled, single-celled plankton) peaked at the equator and has been dropping there ever since. This is significant as plankton is a keystone species in the foodweb.

Our study shows that decline has accelerated in recent decades due to human-driven climate change.

The profound implications

Losing species in tropical ecosystems means ecological resilience to environmental changes is reduced, potentially compromising ecosystem persistence.

In subtropical ecosystems, species richness is increasing. This means there’ll be species invaders, novel predator-prey interactions, and new competitive relationships. For example, tropical fish moving into Sydney Harbour compete with temperate species for food and habitat.

This could result in ecosystem collapse — as was seen at the boundary between the Permian and Triassic periods — in which species go extinct and ecosystem services (such as food supplies) are permanently altered.

The changes we describe will also have profound implications for human livelihoods. For example, many tropical island nations depend on the revenue from tuna fishing fleets through the selling of licenses in their territorial waters. Highly mobile tuna species are likely to move rapidly toward the subtropics, potentially beyond sovereign waters of island nations.




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Similarly, many reef species important for artisanal fishers — and highly mobile megafauna such as whale sharks, manta rays and sea turtles that support tourism — are also likely to move toward the subtropics.

The movement of commercial and artisanal fish and marine megafauna could compromise the ability of tropical nations to meet the Sustainable Development Goals concerning zero hunger and marine life.

Is there anything we can do?

One pathway is laid out in the Paris Climate Accords and involves aggressively reducing our emissions. Other opportunities are also emerging that could help safeguard biodiversity and hopefully minimise the worst impacts of it shifting away from the equator.

Currently 2.7% of the ocean is conserved in fully or highly protected reserves. This is well short of the 10% target by 2020 under the UN Convention on Biological Diversity.

Manta ray with other fish
Manta rays and other marine megafauna leaving the equator will have a huge impact on tourism.
Shutterstock

But a group of 41 nations is pushing to set a new target of protecting 30% of the ocean by 2030.

This “30 by 30” target could ban seafloor mining and remove fishing in reserves that can destroy habitats and release as much carbon dioxide as global aviation. These measures would remove pressures on biodiversity and promote ecological resilience.

Designing climate-smart reserves could further protect biodiversity from future changes. For example, reserves for marine life could be placed in refugia where the climate will be stable over the foreseeable future.

We now have evidence that climate change is impacting the best-known and strongest global pattern in ecology. We should not delay actions to try to mitigate this.

This story is part of Oceans 21

Our series on the global ocean opened with five in-depth profiles. Look out for new articles on the state of our oceans in the lead-up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.




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The Conversation


Anthony Richardson, Professor, The University of Queensland; Chhaya Chaudhary, , University of Auckland; David Schoeman, Professor of Global-Change Ecology, University of the Sunshine Coast, and Mark John Costello, Professor, University of Auckland

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

Climate explained: rising carbon emissions (probably) won’t make the Earth uninhabitable


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Laura Revell, University of Canterbury


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Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz


Even with all humanity’s carbon emissions to date, there’s a lot less carbon dioxide in Earth’s atmosphere than Venus, and Earth is further away from the Sun. But if carbon emissions continue at the current rate, is there any risk of reaching a tipping point at which a runaway greenhouse effect takes over, making Earth uninhabitable for any form of life?

When sunlight enters the Earth’s atmosphere, some is reflected back to space by clouds, some is reflected by bright surfaces such as ice and snow and some is absorbed by the land surface and ocean.

To maintain a balance, the Earth emits energy back to space in the form of infrared, or longwave, radiation. Some longwave radiation is absorbed in the atmosphere by heat-trapping gases, such as carbon dioxide.

This is the well-known greenhouse effect.




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As is already well established, concentrations of carbon dioxide have increased over the past 250 years, causing the average surface temperature to increase.

One consequence of increasing atmospheric carbon dioxide concentrations is that, as the atmosphere warms, it can contain more water vapour. Since water vapour is itself a greenhouse gas, this can create an amplifying effect.

In general, as surface temperature increases, the Earth emits more longwave radiation to space to maintain the energy balance. But there is a limit to how much longwave radiation can be emitted.

If the atmosphere becomes completely saturated with water vapour, the Earth’s surface and lower atmosphere warm up, but further increases in emission of longwave radiation are not possible.

The runaway greenhouse

This is termed a runaway greenhouse and would mean the Earth would become lethally hot and unable to cool itself by emitting heat to space.

Ultimately, this is the fate of the Earth. In billions of years from now the Sun will become brighter and grow into a Red Dwarf. As the Sun’s luminosity increases, the Earth will become hotter and its oceans will evaporate.

We’re doomed … but not for billions of years.

The hot and steamy atmosphere will ensure the Earth is just as uninhabitable to current life-forms as Venus is today.

But could we bring such a situation about on a shorter timeframe through continued carbon dioxide emissions? The good news is, probably not.

We’re safe, for now

Previous research has found that, due to differences in the properties of water vapour and carbon dioxide as greenhouse gases, adding carbon dioxide to the atmosphere is likely insufficient to trigger a runaway greenhouse.

Atmospheric carbon dioxide is currently around 416 parts per million (ppm) – up from approximately 280 ppm since the first industrial revolution began, some 250 years ago.

In geological terms, this is a very large increase to take place over a short period of time. Yet human emissions of carbon dioxide are considered insufficient to trigger a runaway greenhouse, given the fossil fuel reserves available.

The Earth should be safe from a runaway greenhouse developing for at least another 1.5 billion years.

But then …

The caveat to all the above is that the models scientists use to study future climate are built based on past, known conditions. It is therefore difficult to predict how certain parts of the climate system might operate under extremely high greenhouse gas emissions scenarios.

Clouds hiding the Sun but with rays of light emerging from behind top.
Clouds can reflect sunlight back to space.
Flickr/scheendijk, CC BY

For example, clouds can reflect sunlight back to space, or they can trap heat emitted by the Earth. In a warming world, scientists are still unclear on the role clouds will play.




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While a runaway greenhouse would make Earth completely uninhabitable to life as we know it, the losses that may accrue from just a few degrees Celsius of global warming are serious and must not be discounted.

Sea level rise, increased frequency and intensity of extreme weather events, threats to endangered species and unique ecosystems are just a few of the many reasons we have to be concerned.

The silver lining is we (probably) don’t need to worry about becoming like our neighbour Venus any time soon.The Conversation

We’re not heading this way just yet.

Laura Revell, Senior Lecturer in Environmental Physics, University of Canterbury

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