Tag: Mitigation

Climate change will not impact everyone the same way; but we do not know how

Posted on by janet.crompton
The National Guard rescuing a flood victim. Credit The National Guard, Flickr, CC BY 2.0.

Climate change is affecting the lives of billions of people. The impacts range from water scarcity and food production to health and wellbeing. Climate change impacts are felt in the cities and settlements where people live. We have heard many times that we need to ensure no one is left behind in climate change adaptation and mitigation. To ensure that every voice matters, the impacts of climate change on different groups have to be taken into account. Many individuals or groups are disproportionately affected by climate change as they have less capacity to prepare for, respond to, and recover from climate-related hazards. Worldwide, there are more than one billion persons with disabilities, 15% of the world’s population. The preamble of the Paris Agreement states that parties should respect, promote and consider their respective obligations on human rights and the rights of persons with disabilities, when taking action to address climate change.

Hence, IPCC working group II (WGII) 6th assessment report which was released earlier this year emphasizes not only the warming, drought and floods, but also how much we are exposed to these hazards. There is a renewed focus on vulnerability to climate change which varies strongly between regions and groups of people.

Germany currently holds the G7 presidency, an inter-governmental political forum consisting of several large global north industrial nations. The German Federal Government Commissioner for the Interests of the Disabled called for an Inclusion summit, the first of its kind, in September in Berlin. The main aim was to address questions around impacts of COVID-19, Artificial Intelligence, and climate change on persons with disabilities.

I have never before taken part in such an event, and it was a steep learning curve. Not only were there bilateral meetings between nations, but also the Internal Disability Alliance (IDA), had bilateral meetings with the academics who were invited to speak. The presentations were translated to international sign language, subtitled, and we implemented guidance to make these more accessible. Presenting to a group where many of the participants had visual impairments is different to the typical presentations a natural scientist is focusing on.

The climate change research was presented by Sebastien Jodoin (from McGill) and myself. Sebastien focused on the lack of inclusion of disability rights in the climate emergency. Fewer than one in four countries mentioned disabled people in their national climate plans. My contribution focused on pointing out the lack of knowledge on impacts of and adaptation to climate change in the context of persons with disability. The limited research in the climate change context focusses on heat and other extreme events. Vulnerability to climate change of persons with disabilities is not covered in the literature and therefore not assessed in the report. Disability is therefore only discussed as a category of vulnerability, as part of lists of old people, young people, marginalized and disabled. But these groups have different challenges and vulnerabilities.

So what was the outcome? IDA emphasized the importance of inclusion as a driver for change. The Chairs summary emphasized the importance of comprehensive statistical and research data to inform the design of policy aiming to identify and address barriers faced by persons with disabilities in exercising their rights.

Environmental justice ensures that socially vulnerable segments of the population should not be disproportionately affected by adverse environmental impacts or hazards. Often actions start at a local scale. In Bristol the Bristol Disability and Equality Forum is working towards inclusion on the city scale, based on their community climate action plan. Emma Green, their climate action coordinator, helped me to consider costs and benefits of climate adaptation more broadly than I did before. Environmental justice asks us all to make sure we consider the needs of everyone while we adapt to and mitigate to climate change. Subregional disaggregation will allow us to determine groups who have the information, skills and funds to implement climate adaptation and reduce their vulnerability, and those who will need support.

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This blog is written by Cabot Institute for the Environment member Professor Daniela Schmidt, School of Earth Sciences, University of Bristol. Daniela is an IPCC report lead author and lead on the recent IPCC WGII chapter on Europe.

Professor Daniela Schmidt

 

 

 

IPCC blog series – Working Group 3 – Mitigation of climate change

Posted on by janet.crompton

This blog is part of a series on the Intergovernmental Panel on Climate Change’s recent 6th Assessment Report, with this post covering the output of Working Group III and the proposed solutions and mitigations for the climate crisis. This article also features a chat with IPCC Lead Author Dr Jo House and contributor Viola Heinrich, researchers at the University of Bristol and Cabot Institute for the Environment. 

Of the three Working Groups, the third makes for the most positive reading. As the title suggests, this one is all about the mitigation of climate change and preventing the disastrous climate futures explained by Working Groups I and II. Whilst remaining focussed on the impending nature of the climate crisis, this report spells out that we have the solutions.

As discussed in the previous posts, massive behavioural changes are needed at government and societal levels. When I spoke to academics, they were positive that we were well past the point of whether climate change is real or has an impact on humanity and that economically minded leaders are starting to see the benefits of sustainable practice and the economic security it brings. Governments and states are listening and looking at policy to mitigate the crisis.

Let’s look at some of the solutions and mitigations proposed:

The quicker we act, the less economic impact

This follows on nicely from previous reports that stated the effects of warming increase with each incremental global average temperature increase. That is to say, a +1.5 degrees C future will see less devastation than a +2 degrees C or even a +1.7 degrees C rise in temperature. Such disasters (drought, extreme weather, flooding) require huge amounts of money resources to sort out. From an economic security point of view, it makes complete sense to act with great urgency. The climate crisis is already here, and therefore already having an economic impact. Action immediately will mitigate against the future potential costs of a climate disaster.

Relative to the economic impact of climate disaster in the future, the investment of reducing the impact of the crisis and securing a liveable planet is small.

The immediate reduction of fossil fuel production and limitation of greenhouse gases in the pursuit of Net Zero

As discussed before, the greatest culprit of the climate crisis is unequivocally greenhouse gas (GHG) emissions from fossil fuels. Therefore, in an ideal world, the immediate halt of fossil fuel extraction, production and consumption would be enough to prevent an overshoot +1.5 degrees C (as discussed in the first report, there is a lag between emissions and warming). Unfortunately, this is not an ideal world, so significant policy to pursue a Net-Zero will be needed.

Going further, carbon must also be removed from the atmosphere somehow, to allow the planet to return to preindustrial atmospheric carbon levels.

Carbon removal, naturally and technologically

A key aspect to the third Working Group is its arguments for carbon capture. This could be either through natural carbon removal through plants and trees, or by using carbon removal technology through direct air capture.

Carbon capture will be essential to solving the climate crisis, as carbon needs to be removed in order to return to the pre-industrial levels of atmospheric carbon. As well as this, proposed tech allows for carbon to be captured at the source of emissions. The issue is that carbon capture could lead to a dependence on the technology.

Companies, understandably, are drawn to the idea of “planting trees” to offset their emissions. It’s visible, tangible, and easy for the public to grasp. However, it’s not always the most efficient use of land and resources, and some worry that these methods will be exploited as a crutch to not reduce emissions output. While an extremely important step in mitigating climate change, some worry that there may be a resultant reliance on carbon removal over carbon emission reduction, allowing the world’s most prolific polluters to continue maintain their carbon output.

One of the most cost-effective mitigation techniques is simply the protection of existing forests and natural sites. The IPCC also stresses that decisions of protection like these must involve the input of the indigenous communities living there.

From the policy level to the personal level

It’s brilliant to be making the personal decisions to limit your own carbon impact, but individuals have limited impact on the climate system. What these reports suggest is wide reaching policy at state level to incentivise populations to make better climate conscious choices, by making things easier through improved infrastructure and methods of “demand management”, reducing the consumption of resource intensive products like meat and dairy. Diet changes at a population scale will be needed to combat the emissions of methane (another greenhouse gas) in particular.

In urban environments, investment in public transportation and cycling infrastructure would go a long way to reduce emissions. As would policy that makes retrofitting buildings to be more energy efficient and building new infrastructure with energy efficiency in mind.

For a great bit of further reading, the IPCC Special report on Climate Change and Land goes into much further detail about the impact of changing diets and consumption habits at scale.

Read the IPCC Special Report on Climate Change and Land

As previously discussed in the blog post on the WGII report, the impacts of climate change are not equal or in proportion to climate impact of the nation affected. Therefore, much of the mitigation will need to take the form of humanitarian aid, improving infrastructure for nations without the resources to do so themselves.

The IPCC reports end on a poignant note: “International cooperation is a critical enabler for achieving ambitious climate change mitigation goals”.

Insight from IPCC Lead Author Dr Jo House and contributor Viola Heinrich

Dr Jo House

Dr Jo House is Reader in Environmental Science and Policy, Research Lead of Cabot Institute for the Environment’s Environmental Change theme and a Lead Author on the IPCC’s AR6 Working Group III report.

Viola Heinrich is a Physical Geography PhD Candidate at the University of Bristol, studying the emissions and climate mitigation potential within the land use sector in the tropics, especially the Brazilian Amazon. Viola assisted Dr House in her AR6 work, producing figures for WG III.

How did you get involved with the IPCC and WGIII?

Dr Jo House – “I have been working on IPCC reports for 20 years. I was first employed as a chapter scientist to support the chapter team for working group I, 3rd assessment report carbon cycle chapter. I was then made a lead author for the synthesis report for AR3. Since then, I have been a lead author or contributing author on all three Working Groups, as well a lead author for the Special Report on Climate Change and Land. I am also a lead author twice for the IPCC Task Force on Inventories, who provide methodological guidance to countries on how to produce their greenhouse gas inventories, for reporting to the UNFCCC, as well as accounting under the Kyoto Protocol.

Viola Heinrich

Despite the long hours and the many thousands of comments we must respond to, I do IPCC because I care about climate change, and IPCC gets the science into the hands of people who can do something about it.”

Viola Heinrich – “I’m a PhD student working on understanding the emissions and climate mitigation potential within the land use sector in the tropics, especially the Brazilian Amazon. Jo, as my supervisor, approached me in 2019 to help produce some figures for her work on AR6 and WGIII.

It was a great learning experience seeing how these report cycles work and one bonus was that the work I produced for the IPCC reports was able used in the introduction to my PhD thesis”

What’s one key message you’d like to highlight from WGIII?

Dr Jo House – “We are nearly already too late to stay within 2 degrees, so we need to reduce fossil fuels usage drastically and rapidly to avoid even worse impacts.

Also specifically from a land perspective: The land has potential for mitigation, but it cannot do it all, planting trees is not a get out of jail free card for continuing to burn fossil fuels.”

Viola Heinrich – “This report has followed nicely on form previous cycles in that it has reaffirmed what we know about the land use component and the mitigation potential of the land use sector (20% to 30% by 2050). The big caveat of course is that the land can’t do it all and we need to be actively reducing emissions rather than relying in capture methods from trees for example.

Another interesting factor about the report is that it stresses the importance of considering the local communities in places where solutions and mitigations take place, seeking their expertise in protection, and understanding how these actions will affect them.”

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As always, we recommend taking a look at the IPCC’s full reports and report summaries for yourself if you seek to further understand the evidence and reasoning behind their headline statements.

That wraps up the blog series, I hope that it was enjoyable and informative.

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This blog series was written by Cabot Communications Assistant Andy Lyford, an MScR Student studying Paleoclimates and Climate modelling on the Cabot Institute’s Master’s by Research in Global Environmental Challenges at the University of Bristol.

Andy Lyford

 

 

Introducing our IPCC blog series

Posted on by janet.crompton

 

This blog is the first part of a series from the Cabot Institute for the Environment on the Intergovernmental Panel on Climate Change’s recent Sixth Assessment Report (IPCC AR6). This post is an introduction to the blog series, explaining what we’re aiming to do here and with a glossary of some climate change terms that come up in the later posts. Look out for links to the rest of the series this week.

What is the IPCC?

The IPCC is the Intergovernmental Panel on Climate Change. Formed in 1988 by scientists concerned about the state of the global climate, they’ve been publishing assessment reports on the climate to advise policymakers and governments to act. This year they published their 6th assessment report (AR6), which has been described as their ‘starkest warning’ about the dangers of climate change. The report was built up of 3 Working Groups and over 2800 experts representing 105 countries covering different aspects, from the base science to the sociological impacts of a climate crisis. Alongside their assessment reports, the IPCC also publish special reports on key issues to explore them in more detail. These topics have included Land Use, Impact on the Ocean and Cryosphere and further clarifications on the goal of mitigating 1.5°C global warming.

The IPCC are the most trusted climate group worldwide, with their work being used in policy decisions all over the world.

What are the three Working Groups?

Each of the working groups focuses on a different part of the climate story, looking at causes, effects, and solutions.

• Working Group 1: The Physical Science Basis (WGI)

• Working Group 2: Impacts, Adaptation and Vulnerability (WGII)

• Working Group 3: Mitigation of Climate Change (WGIII)

What is this blog series covering?

The full reports are well over 1000 pages each, with many chapters, subchapters, and footnotes to wade through. As previously mentioned, the full report is split into the domains of the working groups.

Each report from the Working Groups is then filtered down into its own Summary for Policy Makers, which is still dense and features a lot of explanation of evidence. This is further broken down into the headline statements that get released to the press. Even at this level, it’s hard for ordinary members of the public to take the time to read all the evidence and digest the key points.

The aim of this campaign is to distil the key points in each Working Group report in a short, easily understood, and shareable blog as a tool for public outreach. As well as this, the campaign will feature voices from across the Cabot Institute for the Environment including IPCC authors from each of the working groups.

It’s a nearly impossible job trying to filter down the output of thousands of experts into a digestible snippet, but hopefully readers will come away more informed about the IPCC reports and the climate crisis than before.

This week, we’ll be sharing my report summaries here on the Cabot Institute for the Environment blog as well as on Twitter and LinkedIn, starting this Wednesday [27 July] on the output of Working Group I: The Physical Science basis. Keep an eye out for it!

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This blog campaign was written by Cabot Institute Communications Assistant Andy Lyford, an MScR Student studying Paleoclimates and Climate modelling on the Cabot Institutes’ Masters by Research in Global Environmental Challenges program at the University of Bristol.

Climate Change 2022: Impacts, Adaptations and Vulnerability – an IPCC lead author report summary

Posted on by janet.crompton

Professor Daniela Schmidt, a lead author of the recently published IPCC (Intergovernmental Panel on Climate Change)  report, Working Group II: Impacts, Adaptations and Vulnerability, recently gave an internal presentation to University of Bristol staff to summarise the report’s findings.

Recent geo-political events have meant that this report has understandably been overlooked in comparison to its predecessor, however, at 3500 pages and being the product of analysis of 34,000 papers since 2014, it is certainly not light reading. This writing aims to pinpoint and amplify the key messages from Daniela’s summary of Working Group II: Impacts, Adaptations and Vulnerability, as the Working Group III: Mitigation of Climate Change report has been released this week.

Solutions

The key take home message, was that the report offers solutions, but they are needed now. Daniela explained that it is not all doom and gloom, and it is important for our survival not to take it that way. From the report itself, the key quote, which you have perhaps seen shared elsewhere, is

The science is clear. Any further delay in concerted global action will miss a brief and rapidly closing window to secure a livable future. This report offers solutions to the world.

Nature

One of the key solutions proposed in the report is nature, both in terms of its conservation and restoration and that it offers promising solutions to many of the threats we face. For example, the potential of natural carbon sinks, coastal protection, water management and urban cooling systems has been repeatedly evidenced, as well as the importance of integrating nature and natural solutions into urban spaces.

The report stresses that humans are part of ecosystems, not separate from them, and nature is crucial to our survival because of the essential and irreplaceable ecosystem services it provides. Fragmented, polluted and overexploited ecosystems are much more vulnerable to climate change, therefore, the report stresses it is therefore important to take a coordinated approach, with their protection and restoration in mind.

Interconnection

As well as the interconnectedness of humans and nature, the report evidences previously unrealised interconnections of climate risks. Risks are becoming more complex and there are compound and cascading risks through systems. For example, in terms of food scarcity, we need to consider that heat stress will not only reduce crop yields, but also the well-being and productivity of farm workers, further exacerbating the situation. There is an increased recognition of the interconnections between people, regions, society, ecosystems, biodiversity. This means that climate change cannot be seen as an individual problem, but as one intrinsically linked with natural resource depletion, ecosystem destruction, and growing urbanisation and inequity across the world.

Equality

Another key focus of the report was the importance of but lack of global equality, which will continue to be exacerbated in the face of climate change. 3.3  – 3.6 billion live in hotspots of high vulnerability to climate change, due to high levels of poverty, limited access to water, sanitation and health services, climate sensitive livelihoods and lack of funding and accountability in government. I would like to point out, that in the vast majority of cases, it is these communities whose carbon contributions are the least, which in my opinion strongly evidences to the fact that climate change is a political problem as well as a scientific one.

Due to inequality being a big problem, the report places an emphasis on the importance of promoting equality in the solutions and with this the need to listen to marginalised voices. Daniela explained that of global climate funding, 80% goes to mitigation, or reduction of emissions, while only 20% goes to adaptation, which is likely to be what is most consequential to more vulnerable communities.

After lack of action on deals made at COP26, which scientists have already argued at best would not be sufficient to solve the problem, a continued lack of action following these urgent messages will be deeply concerning for the fate of the planet, and especially for its most vulnerable communities.

Watch Daniela’s presentation to University of Bristol staff.

 

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This blog is written by Cabot Institute for the Environment member Hilary McCarthy, University of Bristol.
Hilary McCarthy

 

Collecting silences

Posted on by janet.crompton

‘Noise’ is the Greenhouse gas (GHG) emissions which have resulted from fossil-fuel-powered economic growth which is measured as GDP for particular territories. In Figure 1, ‘noise’ is the area below the green line to the left of the vertical dotted line (historical) and below the blue line to the right of the vertical dotted line (projected). ‘Silence’ is the reduction of fossil-fuel use and the mitigation of carbon emissions. In Figure 1, ‘silence’ is the green shaded area above the blue line and below the dotted blue line to the right of the vertical dotted line.

Figure 1

To ensure that we maintain atmospheric GHG emission concentrations conducive to human habitation and the ecosystems that support us, we need to assign less value to ‘noise’ (burning fossil fuels) and more value to ‘silence’ (GHG emission mitigations). Creating a system which assigns value to ‘silences’ by turning them into investable resources requires an effort sharing mechanism to establish demand and organizational capacity alongside accurate measuring, reporting and verification for supply.

Organizational capacity for supplying ‘silences’ depends on the ability of organizations to create, trade and accumulate GHG emission mitigations. Due to the intangible nature of such ‘silences’, turning GHG emissions mitigations into investable sources requires their assetization as quasi-private goods with well-defined and delineated quasi-property rights. As preservations of the intangible commodity of stable atmospheric GHG concentrations through the reduction of pollution, such rights need to protect investment by ensuring that these private goods are definable, identifiable and capable of assumption by third parties. Such rights also require enforcement and protection against political and regulatory risk.

Commodifying GHG emission mitigations as quasi-private goods by assetizing them with well-defined and delineated quasi-property rights therefore provides the basis for the supply of ‘silences’. Rather than ‘internalising’ the cost of stabilising or reducing atmospheric GHG concentrations, this approach assigns value to GHG emission mitigations. Yet, if we want to avoid climate catastrophe according to the most recent IPCC 1.5C report and the UNDP Emissions Gap Report, GHG emission mitigations also require concretization on the demand-side. There are several examples of GHG emission mitigation and energy demand reduction assetization that can help illustrate how such systems of demand and supply can function.

Similar to GHG emission mitigations, energy demand reductions also represent the reduction of an intangible commodity vis-à-vis a baseline. While stable atmospheric GHG emission levels are the intangible commodity in the case of the former, in the case of the latter the intangible commodity is energy supply which fuels economic growth. Both require the assetization of mitgations/reduction to create ‘tangibility’, which provides the basis for assigning value. To illustrate, energy demand reductions are absent on domestic and corporate accounts and subsequently undervalued vis-à-vis increases in revenues.

Market-based instruments that succeed in setting and enforcing targets and creating systems of demand, however, can create ‘tangibility’. Energy demand reductions, for example, are assetized as white certificates representing equal units of energy savings (negawatts) in white certificate markets. Similarly, demand-side response enables the assetization of short-term shifts in energy (non-)use (flexiwatts) to benefit from flexibility and balancing markets. Carbon emission mitigations are assetized under the Clean Development Mechanism (CDM) as Certified Emissions Reductions (CERs).

Crucially, these examples shift the emphasis from the cost of pollution and the need to ‘internalise’ this cost or from turning pollution into a quasi-private good through Emissions Trading Schemes (ETS) towards the positive pricing of energy demand reductions and carbon emission mitigations. Positive pricing turns their respective reduction and mitigation itself into a quasi-private good by turning ‘silences’ into investable resources.

The main technical difficulty of establishing such systems lies in the definition of baselines and measuring, reporting and verification vis-à-vis these baselines. The difficulties inherent in this approach are well documented but improved sensing technology, such as the Internet of Things (IoT), and distributed ledgers promise greatly improved granularity and automated time-stamping of all aspects of energy (non-)use at sub-second intervals. If structures of demand are clearly identified through target-driven market-based instruments and supply is facilitated through the assetization of ‘silences’ as quasi-private goods with clearly defined and enforced quasi-property rights, a clear incentive also exists to ensure that MRV structures are improved accordingly.

Key to the implementation of such target-driven market-based instruments are mechanisms to ensure that efforts are shared among organisations, sectors or countries, depending on the scale of implementation. Arguably, one of the reasons why the CDM failed in many aspects was because of the difficulty of proving additionality. This concept was supposed to ensure that only projects that could prove their viability based on the availability of funds derived from the supply, trade and accumulation of CERs would be eligible for CDM registration.

The difficulty of proving additionally increases cost and complexity. To ensure that new mechanisms no longer require this distinction, a dynamic attribution of efforts is required. A mechanism to dynamically share efforts can also help address rebound effects inherent in energy efficiency and energy demand reduction efforts. Key is the target-driven nature of associated market-based instruments and the equitable distribution of the rebound through a dynamic mechanism which shares any rebounds (i.e. increases in carbon emissions) equitably among organisations, sectors or countries. With an appropriate effort-sharing mechanism in place, the demand and supply of ‘silences’ can be aligned with targets aiming to maintain atmospheric GHG emission concentrations in line with levels conducive to human habitation and the ecosystems that support us.

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This blog is written by Cabot Institute member Dr Colin Nolden, a Vice Chancellor’s Fellow in sustainable city business models. The blog has been reposted with kind permission of World Sustainable Energy Days. If you would like to read more on this topic, you can read Colin’s research paper here.

Colin Nolden

 

Downhill all the way: Monitoring landslides using geophysics

Posted on by janet.crompton

Developments in geophysical methods used to monitor surface and subsurface changes prior to landslides can lead to improved prediction and early warning.

Drone photo from the Hollin Hill Landslide Observatory in North Yorkshire, UK, taken in August 2018. This landslide exhibits progressive “slip-stick” failure, which is linked to increases in subsurface moisture-content caused by prolonged and extreme precipitation. This backscarp feature, located in Lias Group mudrocks (Whitby Mudstone Formation), has developed slowly since first appearing in April 2016. Prior to this, there were few clues at the ground surface indicating the impending failure. Credit: British Geological Survey

 

Every year, landslides cause fatalities and destruction in locations worldwide. Nevertheless, what triggers them and when they occur can often be difficult to predict. A recent article in Reviews of Geophysics examined developments in landslide monitoring using insights and methods from geophysics. Here, one of the authors of the paper answers some questions about landslide monitoring and prediction.

Why is the monitoring of landslides important, and what role can geophysics play?

Sometimes the most effective option for mitigating the risk from landslides is monitoring.

In an ideal world, we would have the geotechnical and financial resources to be able to remove all landslide hazards through slope stabilization and remediation. In reality, this just isn’t possible, and sometimes the most effective option for mitigating the risk from a landslide is to monitor it.

Historically, this has been done by monitoring deformation at the surface and by looking at changes from localised points in the subsurface; for example, by measuring fluctuations in the water table in a borehole. Variations in these data may provide clues about when slope failure is imminent.
The advantage of geophysical methods is that they can not only monitor subsurface properties and how they change over time but can also do so at much higher spatial resolution and over a wider area than point sources of information, such as boreholes.

What are the different types of landslides and why are geophysical methods particularly useful for monitoring “moisture-induced” landslides?

“Landslide” is one of those words that sounds simple enough to define but in reality is very complex.

One of the distinctions we can make between landslide types is their triggering mechanism; most landslides are caused by the direct consequences of increased rainfall and shaking by earthquakes, but they can also be a result of secondary factors such as deforestation.


Between 2007 and 2016, 83% of landslides globally were triggered by rainfall or other hydrological events. This is why we use the term “moisture-induced” in our review article, as it reflects the complicated nature of all sources of water present in landslide systems, including rainfall, snow-melt, and groundwater, amongst others.

Introducing increased amounts of water into a landslide changes the properties of the subsurface, which leads to destabilization and, when a critical threshold is exceeded, slope failure. These changes in material properties can be monitored by geophysical methods and, by comparing data collected over time, it is possible to make inferences about the destabilizing processes that are occurring in the subsurface of the landslide system.
Changes in subsurface ground moisture derived from a semi-permanent, 3D electrical resistivity (ER) array at the Hollin Hill Landslide Observatory, North Yorkshire, UK. The left image shows wet winter conditions, in which the western lobe of the landslide has significantly more subsurface moisture than the eastern lobe. The right image shows drier summer conditions, showing subsurface drainage from the failing Whitby Mudstone Formation to the underlying Staithes Sandstone Formation, despite dry ground at the surface of the landslide. Credit: Uhlemann et al. [2017], Figure 11

 

What different geophysical methods are used to gather information about moisture-induced landslides?

The majority of studies used passive seismic and active geoelectrical methods.

Our review article looks at published case studies from the past 12 years to see what kinds of methods are being applied to monitor moisture-induced landslides. What struck us was that the majority of studies used one of two methods: passive seismic and active geoelectrical methods.


Passive seismic monitoring has been used for many decades in global seismological studies, but really only started to be scaled down to look at smaller scale features, such as landslides, in the mid-1990s.

Although passive seismic monitoring has been around longer, monitoring landslides using active geoelectrical methods, primarily electrical resistivity (ER), has really taken off in the last decade or so. There have been several studies in which ER technologies have been developed specifically for landslide monitoring approaches. Consequently, ER monitoring is currently able to provide more information than passive seismic monitoring on the pre-failure conditions of landslides.
Lower equipment costs and power consumption, combined with better data management and equipment durability, means we can collect more geophysical data for longer from landslides. Each of the points in this plot shows information gathered from published case studies about the length of time and amount of data acquired during a single geophysical monitoring campaign. Multiannual campaigns are becoming increasingly common compared to nearly a decade ago. Credit: Whiteley et al. [2018], Figure 6

 

What do these methods tell us about the subsurface conditions of landslides?

The two approaches provide an opportunity to better understand the variable nature of the subsurface in time and space.

Passive seismic and active geoelectrical approaches complement each other very well. First, they tell us about different aspects of the subsurface conditions beneath a landslide. Seismic methods are able to tell us about the strength of the ground, while ER methods provide information about subsurface moisture dynamics. Both of these aspects are very important when trying to predict landslide movements.


Second, passive approaches tend to have great temporal resolution, but their spatial coverage can be limited by the number of seismic sensors deployed on a slope, usually due to cost or power requirements. On the other hand, ER methods can provide very high spatial resolution, but as they are dependent on collecting a set of data from many measurements, their temporal resolution can be limited. Together, the two approaches provide an opportunity to better understand the variable nature of the subsurface in time and space.

What advances in equipment and data analysis have improved understanding of landslide processes?

The financial, computational, and energy cost of equipment is continually reducing, which means we can collect more data for longer periods, and send data from the field to the lab for near real-time analysis.

Also, data telemetry means we can send data from the field to the lab for near real-time analysis. Both of these are crucial when using geophysical methods for early-warning of landslide failure.

Recently, there has been an increase in the use of 3D surveys and petrophysical relationships linking geophysical The financial, computational and energy cost of equipment is continually reducing, which means we can collect more data for longer periods. Also, data telemetry means we can send data from the field to the lab for near real-time analysis. Both of these are crucial when using geophysical methods for early-warning of landslide failure.

In ER monitoring, movements in the electrode array would have historically produced errors in the resistivity model, but developments in ER data inversion can now use this source of “error” to track movements in the landslide. Similarly seismic “ambient noise” is being used in innovative ways to monitor landslides, even though these background signals would have traditionally been undesirable in seismological surveys.

Left: The “Automated time-Lapse Electrical Resistivity” (ALERT) geoelectrical monitoring system installed at Hollin Hill, North Yorkshire, UK. Right: Inside the cabinet, the system acquires geoelectrical, geotechnical and weather data. Collecting geophysical measurements alongside local displacement and environmental data allows for more robust interpretations of the changes in subsurface geoelectrical data over time. Credit: British Geological Survey

Where is the field of geophysical monitoring of moisture-induced landslide heading?

The challenge now is to start looking for clues to identify precursory conditions to slope failure and to develop geophysical thresholds to inform early-warning approaches. 

The great news is that this is a very active area of research! There is a lot of work being done in environmental seismology to increase the number of low-cost, low-power seismic sensors that can be deployed in landslide settings. This is important, as it will allow us to monitor landslides at very high-resolution in both the spatial and temporal domain.

Looking to the future, one can envision “smart sensor” sites that provide power, data storage, and telemetry, accommodating a wide range of integrated geophysical, geotechnical, and environmental monitoring methods. These could include seismic and electrical arrays, wireless sensor networks, and weather stations, with data relayed back to central processing sites for near-real time assessment, and early-warnings of impending failure based on calibrated geophysical thresholds.

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This blog was written by Cabot Institute for the Environment member James Whitely, postgraduate researcher at University of Bristol’s School of Earth Science and the British Geological Society, with contributions from the articles co-authors. The blog was originally published by Editors’ Vox.


Original blog Citation: Whiteley, J. (2019), Downhill all the way: monitoring landslides using geophysics, Eos, 100 https://doi.org/10.1029/2019EO111065

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