Exaggerating how much CO₂ can be absorbed by tree planting risks deterring crucial climate action



A long way to go…
Amenic181/Shutterstock

Duncan McLaren, Lancaster University

Planting almost a billion hectares of trees worldwide is the “biggest and cheapest tool” for tackling climate change, according to a new study. The researchers claimed that reforestation could remove 205 gigatonnes of carbon from the atmosphere – equivalent to about 20 years’ worth of the world’s current emissions. This has criticised as an exaggeration. It could actually be dangerous.

While the paper itself included no costings, the researchers suggested a best-case estimate of just US$300 billion to plant trees on 0.9 billion hectares. That’s just 40 US cents per tonne of carbon dioxide (CO₂) removed. More detailed studies on the costs of carbon removal through reforestation put the figure closer to US$20-50 per tonne – and even this may be optimistic at such large scales.




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Our research suggests that the promises implied in such studies could actually set back meaningful action on climate change. This is because of what we call “mitigation deterrence” – promises of cheap and easy CO₂ removal in future make it less likely that time and money will be invested in reducing emissions now.

Why would anyone expect governments or the finance sector to invest in renewable energy, or mass transit like high-speed rail, at costs of tens or hundreds of dollars a tonne if they – and shareholders and voters – are told that huge amounts of CO₂ can be absorbed from the atmosphere for a few dollars a tonne by planting trees?

Why should anyone expect energy companies and airlines to reduce their emissions if they anticipate being able to pay to plant trees to offset everything they emit, for the paltry price of less than 50 cents a tonne. If studies like this suggest removing carbon is cheap and easy, the price of emitting carbon for businesses – in emissions trading schemes – will remain very low, rather than rising to the levels needed to trigger more challenging, yet urgently needed, forms of emission reduction.

Tree planting is cheaper but less effective at reducing emissions than building zero-carbon infrastructure like electric high-speed rail.
Pedrosala/Shutterstock

A false carbon economy

The promises of cheap and powerful tech fixes help to sideline thorny issues of politics, economics and culture. But when promises that look great in models and spreadsheets meet the real world, failure is often more likely. This has been seen before in the expectations around carbon capture and storage.

Despite promises of its future potential in the early 2000s, commercial development of the technology has scarcely progressed in the last decade. That’s despite many modelled pathways for limiting global warming still assuming – increasingly optimistically – that it will be deployed at a large scale in coming decades.




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This model of tackling climate change goes hand in hand with another tool – pricing carbon emissions. This potentially allows companies to go on emitting by paying someone else to cut emissions or remove CO₂ elsewhere – an approach called climate offsetting. But offsetting makes exaggerated promises of carbon removal even more risky.

Tree planting financed through offset markets would guarantee the polluter could continue emitting carbon, but the market couldn’t guarantee removals to match those emissions. Trees might be planted and subsequently lost to wildfire or logging, or never planted at all.

Trusting in trees to remove carbon in future is particularly dangerous because trees are slow to grow and how much carbon they absorb is hard to measure. They’re also less likely to be able to do this as the climate warms. In many regions of the world but particularly in the tropics, growth rates are predicted to fall as the climate warms and devastating wildfires become more frequent.

Relying on trees to absorb CO₂ from the atmosphere in the future also appears misleadingly cheap because of the effects of economic discounting. Economists discount the current value of costs or benefits more deeply, the further in the future they occur. Models which determine the cheapest mix of policies available all use some form of discounting.

When researchers add carbon removal options like tree planting to these models, they tend to generate pathways for slowing temperature rise which reduce the role of short term action and replace it with imaginary removals late in the century.

This is because discounting over 30 to 60 years makes the removal options look incredibly cheap in today’s prices. Priming models to focus on minimising cost causes them to maximise the use of discounted future removals and reduce the use of more expensive near term emissions reduction.

I am not arguing against reforestation, nor for a purely technological response to climate change. Trees can help for many reasons – reducing flooding, shading and cooling communities, and providing habitat for biodiversity. Incentives for reforestation are important, and so are incentives for removing carbon. But we shouldn’t make trees or technology carry the whole burden of tackling climate change. That demands moving beyond technical questions, to deliver immediate political action to cut emissions, and to begin to transform economies and societies.

This article was amended on July 13 2019 to clarify the proposed costs of carbon removal by reforestation.The Conversation

Duncan McLaren, Professor in Practice, Lancaster University

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

Townsville floods show cities that don’t adapt to risks face disaster


Cecilia Bischeri, Griffith University

A flood-ravaged Townsville has captured public attention, highlighting the vulnerability of many of our cities to flooding. The extraordinary amount of rain is just one aspect of the disaster in Queensland’s third-biggest city. The flooding, increasing urban density, the management of the Ross River Dam, and the difficulties of dealing with byzantine insurance regulations have left the community with many questions about their future.

These questions won’t be resolved until we enhance the resilience of cities and communities against flooding. Adaptation needs to become an integral part of living with the extremes of the Australian environment. I discuss how to design and create resilient urban landscapes later in this article.




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Flood risk and insurance

Another issue that affects many households and businesses is the relationship between insurance claims and 1-in-100-year flood event overlay maps. Projected rises in flood risks under climate change have led to concerns that parts of Townsville and other cities will become “uninsurable” should the costs of cover become prohibitive for property owners.

Council flood data used for urban planning and land-use strategies is also used by insurers to assess the flood risk to individual properties. Insurers then price the risk accordingly.




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However, in extraordinary circumstances, when the flooded land is actually larger than the area marked by the flood overlay map, complications emerge. In fact, that part of the community living outside the map’s boundaries is considered flood-free. Thus, those pockets of the community may have chosen not to have flood insurance and not have emergency plans, which leaves them even worse off after floods. This is happening in Townsville.

Yet this is nothing new. Many people experienced very similar circumstances in 2011. Flood waters covered as much land as Germany and France combined. Several communities were left on their knees.

Notwithstanding the prompt and vast response of the federal government and Queensland’s state authorities, a few years later Townsville is going through something alarmingly similar.

Adaptation to create resilient cities

To find a solution, we need to rethink how to implement the Queensland Emergency Risk Management Framework. That is no easy task. However, it starts with shifting the perspective on what is considered a risk – in this case, a flooding event.

Floods, per se, are not a natural disaster. Floods are part of the natural context of Queensland as can be seen below, for instance, in the Channel Country.

Floods are part of the Australian landscape. Here trees mark the seasonal riverbeds in the Queensland outback between Cloncurry and Mount Isa.
Cecilia Bischeri, Author provided

The concept of adaptation as a built-in requirement of living in this environment then becomes pivotal. In designing and developing future-ready cities, we must aim to build resilient communities.

This is the ambitious project I am working on. It involves different figures and expertise with a shared vision and the support of government administrations that are willing to invest in a future beyond their elected term of office.

Ideas for Gold Coast Resilientscape

I live and work in the City of Gold Coast. Water is a fundamental part of the city’s character and beauty. In addition to the ocean, a complex system of waterways shapes a unique urban environment. However, this also exposes the city to a series of challenges, including flooding.

Last September, an updated flood overlay map was made available to the community. The map takes into account the projections of a 0.8 metre increase in the sea level and 10% increases in storm tide intensity and rainfall intensity.

These factors are reflected in the 1-in-100-year flood overlay. It shows undoubtedly that the boundaries between land and water are changeable.

Building walls between the city and water as the primary flood protection strategy is not a solution. A rigid border can actually intensify the catastrophe. New Orleans and the levee failures during the passage of Hurricane Katrina in 2005 provide a stark illustration of this.

Instead, what would happen and what would our cities look like if we designed green and public infrastructures that embody flooding as part of the natural context of our cities and territory?




Read more:
Design for flooding: how cities can make room for water


The current project, titled RESILIENTSCAPE: A Landscape for Gold Coast Urban Resilience, considers the role of architecture in enhancing the resilience of cities and communities against flooding. The proposal, in a nutshell, explores the possibilities that urban landscape design and implementation provide for resilience.

RESILIENTSCAPE focuses on the Nerang River catchment and the Gold Coast Regional Botanic Gardens, in the suburb of Benowa. The river and gardens were adopted as a case study for a broader strategy that aims to promote architectural solutions for a resilient City of Gold Coast. The project investigates the possibility of using existing green pockets along the Nerang River to store and retain excess water during floods.

Gold Coast Regional Botanic Gardens is one of the green areas along the Nerang River that could be used to store and retain flood water.
Batsv/Wikimedia Commons, CC BY-SA

These green spaces, however, will not just serve as “water tanks”. If mindfully planned, the green spaces can double up as public parks and facilities. This would enrich the community’s social realm and maximise their use and return on investment.

The design of a landscape responsive to flooding can, by improving local urban resilience, dramatically change the impact of these events.

The goal of creating urban areas that are adaptive to an impermanent water landscape is the main driver of the project. New Orleans after Hurricane Katrina and New York after Sandy are investing heavily in this direction and promoting international design competitions and community participation to mould a more resilient future. Queensland, what are we waiting for?




Read more:
Floods don’t occur randomly, so why do we still plan as if they do?



This article has been updated to clarify the use of flood data by insurers in assessing risk and the cost of cover.The Conversation

Cecilia Bischeri, Lecturer in Architecture, Griffith University

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

How can your bank help reduce climate change risks to your home?


Tayanah O’Donnell, University of Canberra

Australia is a land of extreme weather. Events such as the 2009 Victorian bushfires, the 2011 Queensland floods and Cyclone Yasi in 2013 are stark examples of climate-related risks faced by Australian households. Many homes are built in high-risk locations including floodplains, coastlines and bushfire-prone land.

The Climate Institute has today released a report detailing the critical role Australian housing plays in the economy, and the risks housing faces with a changing climate.

It also sets out the role of banks and insurers in promoting risk reduction and climate adaptation for Australian housing.

Built on sand

Housing represents many Australians’ biggest financial commitment – including those who rent rather than buy. Housing accounts for up to one-third of the economy, through direct and indirect means and across sectors such as finance, insurance and construction. With population projections forecasting continued growth and attraction to risky locations, banks and other financial institutions have a crucial role to play in minimising the economic threat posed by climate change.

But while the role of land-use planning and insurance with regard to climate risks has been well documented, the role of banks as gatekeepers to housing finance has been largely overlooked.

As the Climate Institute’s report points out, banks have a “unique ability and incentive” to steer housing purchases, because they are the main providers of residential financing. As such, they have large financial liabilities if homes are lost to fires, floods or other climate effects.

There are a range of tactics banks might use to reduce or mitigate climate risk. For instance, they could favour lending on homes that meet specific risk-reduction requirements, such as raised floor levels for homes in flood zones, or fireproof construction materials in bushfire-prone regions. This approach could also be used in setting mortgage insurance premiums as well as the mortgages themselves. Another approach is to better apportion their exposure – by lending on a reduced percentage threshold of the total property value.

Westpac has a Climate Change Position Statement and both the Commonwealth Bank and NAB have committed in reducing carbon. But more needs to be done for housing.

If banks continue under a business as usual approach, they face the risk that many properties will be devalued over time, through continued exposure to extreme weather events. This represents a significant financial liability, especially when you consider that a home loan typically takes 30 years to play out – a similar time scale to the many climate impacts expected for Australia.

Banks are already making moves to restrict lending based on location.

But the report outlines several other things banks could do, such as:

  • examine climate risk exposure in their current lending practices

  • use their role as financiers to support good policy, by engaging policymakers and financial regulators

  • encourage stakeholders, including the public, private sector and civil society sectors, to develop ways to minimise climate impact risks for housing

  • ensure losses are addressed in an equitable way.

A climate insurance policy

The report also details how the insurance sector assesses risk to housing, and how it might improve its approach in the future, given the intersection of urbanisation, population trends and the trend towards living in climate-threatened areas.

The insurance sector has historically been seen as the messenger of housing market signals, because of its keen focus on assessing weather-related risk. But the 2011 Queensland floods highlighted many weaknesses in relying on insurance alone.

Many properties did not have adequate flood insurance, leaving many people without a home after losing their house to the floods. The Australian and Queensland governments and the private sector struggled to co-ordinate a cost-effective response, partly because of previous bad land-use planning decisions, but also because of the lack of adequate insurance cover.

A federal government levy helped the affected regions to “build better back”. Some chose to rebuild in the same high-risk locations.

Critically, gaps identified in building codes, land use and climate resilience still require a more co-ordinated response. The current Stage 2 coastal law reforms in New South Wales offer a potential example of how competing interests might be balanced.

At face value, this issue is a no-brainer. After all, risk mitigation is bread and butter for lending institutions and insurers, and we already know that extreme weather events are forecast to increase in frequency and severity. National resilience is required.

Quantifying this risk will be easier if financial institutions utilise access to relevant data on issues like coastal risk. Some of these data are becoming more freely available. Recognising the value of climate data is a trend that should continue. For a robust and resilient future, governments and the private sector should end their tango over who should pay for the information and agree that financial climate risks are best faced with eyes wide open.

The Conversation

Tayanah O’Donnell, Research Fellow, University of Canberra

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