DECCMA team members reflect on the experience of working in an international and multi-disciplinary consortium

by Katharine Vincent

The DECCMA team comprises an international, multi-disciplinary consortium all working together to achieve the common goal of evaluating migration as an adaptation in the context of climate change in deltas. In this short clip we outline some of the highlights and challenges of working as part of a consortium, and some lessons learned for future consortium projects.

DECCMA researchers present at European Geophysical Union annual conference in Vienna

by Robert Nicholls and Attila Lazar

A number of DECCMA researchers participated in the recent European Geophysical Union’s annual assembly in Vienna. It is one of the largest conferences in Europe with about 15,000  participants. The focus is on the physical sciences, but it has increasingly cross- disciplinary sessions involving economics, social-sciences and demography.

Attila Lazar from the University of Southampton presented a paper on “Migration and adaptation under climate change in deltas”, discussing a method and the resulting Bayesian network model on the household adaptation (including migration) decisions for male- and female-headed households in Bangladesh, India and Ghana.

Attila Lazar’s presentation to EGU

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DECCMA PI Robert Nicholls co-convened a session on deltas with Steve Darby, Ester Stouthamer (Utrecht) and Hans Middlekoop (Utrecht). Presenters included Frances Dunn (University of Southampton) on present and future sediment fluxes to deltas worldwide, including the DECCMA deltas; Tuhin Ghosh (Jadavpur University) on plausible future aquaculture expansion in the Indian Bengal Delta; and Attila Lazar on possible development trajectories for coastal Bangladesh (based on work funded by the REACH Project).

A large number of posters were also presented, including an overview of the DECCMA project and a lot of work on subsidence in deltas.

The meeting was a good foundation for exchange.  DECCMA researchers discussed future meetings with Dutch colleagues, at EGU and elsewhere, to extend collaboration on  multidisciplinary delta research.

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What does a 1.5⁰C increase in global temperature mean for deltas?

by Robert Nicholls

Deltas are a climate change hotspot, where the effects of climate change coincide with large numbers of people. Sea level rise is a major threat to deltas, bringing risks of flooding and erosion. As the world tries to limit the global temperature increase to 1.5⁰C, the DEltas, vulnerability and Climate Change: Migration and Adaptation (DECCMA) project has been looking at how deltas will be affected by increases in temperature of 1.5⁰C, 2⁰C or 3⁰C.

Volta delta mangroves (photo by Klaus Wohlmann)

Following the historic Paris Agreement, 1.5 ⁰C has become a hot topic.  The Paris Agreement commits developed and developing countries to global temperature increase to 2⁰C, with the aspiration to limit to 1.5⁰C.  These numbers are widely believed to be critical thresholds beyond which significant changes in the natural environment would be experienced (known as planetary boundaries).

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The issue of 1.5⁰C has recently been high on the political agenda again, as the 23rd Conference of the Parties to the UNFCCC met in Bonn to discuss a framework for reporting climate action to monitor the commitments made under the agreement.  Knowing the implications of a 1.5⁰C increase informs the “ambition mechanism”, whereby stocktakes of progress are due to be taken every 5 years, with a view to then revising and updating mitigation and adaptation commitments.  Improvements in science play a key input to ensuring that these commitments remain ambitious and on target to limit the damaging effects of climate change.

Deltas are home to 500 million people worldwide, as well as being natural environments that generate livelihoods, income and essential ecosystem services.  DECCMA has been investigating the effects of climate change in four study sites across three deltas across Africa and Asia: the Ganges-Brahmaputra-Meghna (GBM) megadelta in Bangladesh and the Indian Bengal component in India; and the smaller deltas of Mahanadi in India and Volta in Ghana.

Given the interest in 1.5⁰C, we have used our customised integrated assessment model –the Delta Dynamic Integrated Emulator Model – to look at the likely changes in flooding (in terms of depth of flood and area affected) and the impacts on population in the GBM in Bangladesh under three different scales of temperature increase: 1.5°C, 2.0°C and 3.0°C.

If we continue with relatively high rates of greenhouse gas emissions, models show that a 1.5°C increase could occur from 2011 to 2033.  Rates of temperature increase have already been significant and rapid.  Observed changes in temperature over the 20th century showed an increase in 0.7⁰C.  In comparison, in the readjustment period since the last ice age global temperatures have only increased by between 4-7c over 5000 years.

Sea level rise of 5-14cm is associated with an increase in global temperature of 1.5⁰C.  This may not seem a lot, and it is particularly difficult to find a reference period because sea levels have varied significantly over the last 20,000 years, reflecting glacial periods and the readjustment of land masses.  But, as an indication, sea levels rose by less than 2mm over the 20th century, so the projected increase is over 20 times more than that.

Until 2040 the differences that are likely from a 1.5⁰C increase and a 2⁰C increase are indistinguishable largely due to the year on year variability that is already characteristic of deltas.

If the temperature increase reaches 3⁰C, some of consequences more than double.  The area flooded under 3⁰C is more than 2.5 times that under 1.5⁰C of such sea level rise, for example.  Those at greatest risk are in the central regions and northeast, where there are fewer polders to protect the land.

The good news is that there is still time to implement adaptation – if we act now.  Our team has investigated adaptation and found 93 documented examples in our study deltas spanning agriculture, water management and disaster risk reduction.  We are now in the process of developing an integrated assessment model that will give us insights into adaptation needs and options under various future scenarios.

For more information, see:

Brown Sally, Nicholls Robert J, Lázár Attila, Hazra Sugata, Appeaning Addo Kwasi, Hornby Duncan D, Hill Chris, Haque Anisul, Caesar John and Tompkins Emma, What are the implications of sea-level rise for a 1.5°C, 2°C and 3°C rise in global mean temperatures in vulnerable deltas? Submitted to Regional Environmental Change.

(This blog is also published in the December edition of the CARIAA newsletter)

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Out-migration and effects on women in the Mahanadi delta

DECCMA is committed to providing policy support to develop sustainable, gender-sensitive adaptations within deltaic environments. Taking a gender-sensitive approach to the research process, and ensuring that data can be analysed with a gender lens, are integral to achieving this aim.

Awareness of the importance of gender has increased as a result of global commitments, such as the Convention on the Elimination of all forms of Discrimination Against Women (CEDAW) and the Beijing Platform for Action. The recently-announced Sustainable Development Goals includes one where the aim is to achieve gender equality and empower all women and girls. Gender equality and empowerment of women also features in the text of the Paris Agreement under the United Nations Framework Convention on Climate Change (UNFCCC).

At local level, however, gender differences are pervasive. Understanding context-specific differences in the roles of men and women, and the relations between them, is essential. Only when these are known is it possible to ensure that planned adaptations are equitable and contribute to gender equality.

In this clip, University of Southampton PhD researcher Giorgia Prati explains how she is investigating the effects of out-migration on women left behind in the Mahanadi delta, India.