Daily Archives for October 24, 2019

Water may soon lap at the door, but still some homeowners don’t want to rock the boat



Storm-damaged beachfront homes along Pittwater Road at Collaroy on the northern beaches of Sydney in June 2016.
Dean Lewins/AAP

Vanessa Bowden, University of Newcastle; Christopher Wright, University of Sydney, and Daniel Nyberg, University of Newcastle

It is becoming increasingly possible that sea-level rise of a metre or more will occur this century. You might expect this threat to preoccupy coastal homeowners. But many deny the need to act, for fear their property values will fall.

This particular brand of climate denial presents a conundrum for governments and local councils, which must plan urgently for climate change. The very act of officials identifying homes exposed to sea-level rise can be vehemently opposed by the owners, let alone policies to deal with it.

This is an urgent problem. As long as we keep failing to reduce global carbon emissions, adapting to the inevitable changes in our climate is vital. But winning cooperation from coastal property owners requires more than just talking about the science.

A car covered in sand near Bondi Beach, Sydney after heavy storms in 2015.
David Moir/AAP

A tide of irrefutable facts

An Intergovernmental Panel on Climate Change report released this month warned sea levels are rising faster than we thought. This will lead to more flooding, storm surges and inundation than previously modelled.

In Australia, 85% of people live within 50km of the coast. In 2009, a federal assessment estimated that up to 247,600 Australian homes were at risk of inundation under a 1.1m sea-level rise scenario.



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

Authorities must manage this threat, which might include limiting development, protecting properties, or planning a retreat from some areas.

Yet our research shows that getting community support for such measures can be contentious and time-consuming.

Waterfront properties in Point Piper, Sydney. Some 85% of Australians live near the coast.
JOEL CARRETT/AAP

Property values are king

We researched Lake Macquarie in New South Wales, a council area of about 200,000 residents. Lake Macquarie City Council is a recognised leader in climate adaptation policy.

Lake Macquarie is a large coastal estuary vulnerable to sea-level rise. It has been identified as one of six council areas in Australia at highest risk of inundation. Up to 6,800 buildings in the area – about 10% – could be at risk from sea-level rise and storm surges this century.

In response, the council limited development in the most vulnerable areas and in 2012 began community consultation. This included working with residents to develop an adaptation plan, released in 2016.



Read more:
A landmark report confirms Australia is girt by hotter, higher seas. But there’s still time to act

In 2017 and 2018, we interviewed current and former councillors and council staff, local businesspeople and residents about the consultation process.

We found there was initially strong resistance to the council’s policy attempts. Community members expressed concern that acknowledging the need to adapt to sea-level rise would reduce property prices and increase home insurance costs.

The potential worst-case scenario, being required to abandon one’s home, was strongly resisted by the community.

Heavy machinery moves onto Palm Beach on the Gold Coast to repair cliffs carved out of the front yards of beachfront homes.
Tony Bartlett/AAP

Such community opposition is common across Australia. The Queensland property industry lobbied against state requirements that would have barred new development until climate adaptation plans were in place. At Lakes Entrance in Victoria, coastal residents have complained that adaptation measures are “taking away people’s money … because they’re going to suffer financial loss”.

The problem of climate denialism

In 2012 when community consultation began, property developer Jeff McCloy told the Sydney Morning Herald he was considering suing the council over its policies, describing concern over sea-level rise as “unjustified, worldwide idiocy”.

People have a tendency to want to see or feel the impacts of climate change before they agree to actions they see as conflicting with their priorities.

Property owners who live near oceans or lakes may not have observed rising sea levels or other climate change effects, and sometimes hesitate to believe it will be a future problem, even if flood map modelling shows otherwise.

The proliferation of climate scepticism in public discourse provides ready-made arguments to which some property owners, fearful of climate change impacts, can attach themselves.



Read more:
Climate change: sea level rise could displace millions of people within two generations

We found that these broader debates around climate change impeded Lake Macquarie council’s ability to reach agreement with residents. Those opposing the policy arranged for prominent climate sceptics to speak at public meetings, and published anti-science opinion pieces in the local newspaper.

A yacht washed up on a beach at Little Manly Cove in Sydney in 2012 after wild storms.
AAP/Mick Tsikas

Where to now?

The Lake Macquarie experience shows intensive, long-term, early efforts at community engagement can overcome some community opposition to climate adaptation. After four years of consultation, the council reached agreement with residents in two areas that affected land would be filled in over time, and there would be no forced retreat from homes.

The council is continuing to plan, with community involvement. It is developing suburb-specific adaptation plans designed so residents understand the science and embrace the solutions – including the chance to identify adaptation options themselves.

But across Australia, much work remains. As global carbon emissions continue to rise and the window to act closes, it is crucial that councils, governments and communities plan for whatever the future holds. This includes implementing adaptation plans that get property owners on board.The Conversation

Vanessa Bowden, Postdoctoral research fellow, University of Newcastle; Christopher Wright, Professor of Organisational Studies, University of Sydney, and Daniel Nyberg, Professor of Management, Newcastle Business School, University of Newcastle

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

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Climate explained: how volcanoes influence climate and how their emissions compare to what we produce



Rapid and voluminous volcanic eruptions around 252 million years ago can be linked with a mass extinction event.
from http://www.shutterstock.com, CC BY-ND

Michael Petterson, Auckland University of Technology


CC BY-ND

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

Everyone is going on about reducing our carbon footprint, zero emissions, planting sustainable crops for biodiesel etc. Is it true what the internet posts say that a volcano eruption for a few weeks will make all our efforts null and void?

The pretext to this question is understandable. The forces of nature are so powerful and operate at such a magnitude that human efforts to influence our planet may seem pointless.

If one volcanic eruption could alter our climate to such a degree that our world rapidly becomes an “icehouse” or a “hothouse”, then perhaps our efforts to mitigate anthropogenic climate change are a waste of time?

To answer this question we need to examine how our atmosphere formed and what geological evidence there is for volcanically induced climate change. We also need to look at recent data comparing volcanic and human greenhouse gas emissions.

There is evidence for catastrophic climate change from very large, protracted volcanic eruptions in the geological record. But in more recent times we have learned that volcanic emissions can lead to shorter-term cooling and longer-term warming. And the killer-punch evidence is that human-induced greenhouse gas emissions far exceed those of volcanic activity, particularly since 1950.

Forging Earth’s atmosphere

Let’s go back to first principles and look at where our atmosphere came from. Earth is 4.56 billion years old. The common consensus is that Earth’s atmosphere results from three main processes:

1. remnants of primordial solar nebula gases from the time of earliest planet formation

2. outgassing of the Earth’s interior from volcanic and related events

3. the production of oxygen from photosynthesis.

There have also been contributions over time from comets and asteroid collisions. Of these processes, internal planetary degassing is the most important atmosphere-generating process, particularly during the first of four aeons of Earth’s history, the hot Hadean.

Volcanic eruptions have contributed to this process ever since and provided the bulk of our atmosphere and, therefore, the climate within our atmosphere.

Next is the question of volcanic eruptions and their influence on climate. Earth’s climate has changed over geological time. There have been periods of an ice-free “hothouse Earth”. Some argue that sea levels were 200 to 400 metres higher than today and a significant proportion of Earth’s continents were submerged beneath sea level.

At other times, during a “snowball Earth”, our planet was covered in ice even at the equator.



Read more:
Climate explained: why we won’t be heading into an ice age any time soon

What contribution have volcanic eruptions made to this variation in climate? As an example of a major influence, some scientists link mass extinctions to major volcanic eruption events.

The most famous such association is that of the eruption of volcanoes that produced the Siberian Traps. This is a large region of thick volcanic rock sequences, some 2.5 to 4 million square kilometres, in an area in Russia’s eastern provinces. Rapid and voluminous volcanic eruptions around 252 million years ago released sufficient quantities of sulphate aerosols and carbon dioxide to trigger short-duration volcanic winters, and long-duration climate warming, over a period of 10s of thousands of years.

The Siberian Trap eruptions were a causal factor in Earth’s largest mass extinction event (at the end of the Permian period), when 96% of Earth’s marine species and 70% of terrestrial life ceased to exist.

Natural climate change over past 100 million years

Geological evidence indicates that natural processes can indeed radically change Earth’s climate. Most recently (in geological terms), over the past 100 million years ocean bottom waters have cooled, sea levels fallen and ice has advanced. Within this period there have also been spells of a hotter Earth, most likely caused by (natural) rapid releases in greenhouse gases.

Homo sapiens has evolved during the past few million years largely during an ice age when up to two-kilometre-thick ice sheets covered large areas of the northern continents and sea levels were over 100 metres lower than today. This period ended 10,000 years ago when our modern interglacial warmer period began.

Astronomical cycles that lead to climate variations are well understood – for example, the Milankovitch cycles, which explain variations in Earth’s orbit around the sun, and the periodic nodding/swaying of our Earth’s axis. All of the geological and tectonic causes for this general longer-term Earth cooling are less well understood. Hypotheses include contributions from volcanoes and processes linked to the rise of the Himalayas and Tibet (from 55 million years ago).



Read more:
Climate explained: why we need to cut emissions as well as prepare for impacts

Specific volcanic eruptions and climate impacts

Researchers have studied specific volcanic eruptions and climate change. Mount Pinatubo (Philippines) produced one of the larger eruptions of recent times in 1991, releasing 20 million tonnes of sulphur dioxide and ash particles into the stratosphere.

These larger eruptions reduce solar radiation reaching the Earth’s surface, lower temperatures in the lower troposphere, and change atmospheric circulation patterns. In the case of Pinatubo, global tropospheric temperatures fell by up to 4°C, but northern hemisphere winters warmed.

Volcanoes erupt a mix of gases, including greenhouse gases, aerosols and gases that can react with other atmospheric constituents. Atmospheric reactions with volcanic gases can rapidly produce substances such as sulphuric acid (and related sulphates) that act as aerosols, cooling the atmosphere.

Longer-term additions of carbon dioxide have warming impacts. Larger-scale volcanic eruptions, whose ash clouds reach stratospheric levels, have the biggest climatic impacts: the larger and more prolonged the eruption period, the larger the impacts.

These types of eruptions are thought to have been a partial cause for the Little Ice Age period, a global cooling event of about 0.5°C that lasted from the 15th to the late 19th century. Super volcanoes such as Yellowstone (USA), Toba (Indonesia) and Taupo (New Zealand) can, theoretically, produce very large-volume eruptions that have significant climate impacts, but there is uncertainty over how long these eruptions influence climate.

Perhaps the strongest evidence for answering whether our (human) emissions or volcanoes have a stronger influence on climate lies in the scale of greenhouse gas production. Since 2015, global anthropogenic carbon dioxide emissions have been around 35 to 37 billion tonnes per year. Annual volcanic CO₂ emissions are around 200 million tonnes.

In 2018, anthropogenic CO₂ emissions were 185 times higher than volcanic emissions. This is an astounding statistic and one of the factors persuading some geologists and natural scientists to propose a new geological epoch called the Anthropocene in recognition that humans are exceeding the impacts of many natural global processes, particularly since the 1950s.

There is evidence that volcanoes have strongly influenced climate on geological time scales, but, since 1950 in particular, it is Homo sapiens who has had by far the largest impact on climate. Let us not give up our CO₂ emission-reduction aspirations. Volcanoes may not save the day.The Conversation

Michael Petterson, Professor of Geology, Auckland University of Technology

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

Amazon Rainfall Crisis


With all of the burning and clearing happening in the Amazon rainforest, it was only going to be a short matter of time before a tipping point was reached and now a tipping point appears on the horizon. It would seem only a matter of 1 or 2 years before the Amazon is unable to sustain itself through rainfall. The link below is to an article reporting on the threat posed to the Amazon.

For more visit:
https://www.theguardian.com/environment/2019/oct/23/amazon-rainforest-close-to-irreversible-tipping-point