From Climate Foresight by Francesco Bassetti
Rising sea levels is one of the risks that people most commonly associate with global warming, with more than 600 million people (around 10% of the world’s population) living in coastal areas that are less than 10 meters above sea level.
“What we need is a cross-sectoral approach that faces and solves problems related to sea level rise with a systemic vision of risks that then shares possible actions between different actors.
Considering multiple types of hazards reduces the likelihood that risk reduction efforts targeting one type of hazard will increase exposure and vulnerability to other hazards, in the present and future.
Evaluating risk depends on an analysis of hazard (how much sea levels will rise), exposure (who and what will be affected) and vulnerability (who and what is particularly exposed to the effects).
Therefore, the threats presented by rising sea levels must be evaluated against the specific circumstances of each area.
With fellow researchers, Torresan is working on bringing this approach into policymaking, by applying a multi-criteria methodology to support the analysis and prioritization of risk management measures aimed at enhancing resilience towards climate change-related extreme events for the Metropolitan city of Venice in Northern Italy with the Savemedcoast2 project.Understanding how different land and sea-based drivers – natural and anthropic – shape the evolution of coastal zones at different spatial and temporal scales, and what solutions could be implemented to reduce vulnerability and mitigate environmental and socio-economic risks is of paramount importance to unlock sustainable development pathways.Silvia Torresan, CMCC Foundation
What does this mean for policy decisions?
When talking about sea level rise, accurate predictions are fundamental for both mitigation and adaptation policies.
For mitigation, knowing that different emissions pathways will have a direct effect on future sea levels can act as an added incentive for reducing emissions.
For adaptation, accurate predictions and a multi-risk approach can make all the difference when choosing what strategies to adopt and where and when to apply them.
“Different scenarios, when analysed one by one, lead to a specific prioritisation of the set of risk management measures; while, when the scenarios are analysed together, the prioritisation of the same measures can be totally different.
The necessity to adopt a multi-hazard approach to disaster risk management and climate change adaptation is confirmed by these outcomes developed in the Metropolitan city of Venice using a bottom-up approach with a strong stakeholders involvement in the frame of the BRIDGE project.
Implementing measures strongly oriented to cope with single hazard could lead to an increase of a risk towards other kind of hazards,” explains Anna Sperotto, scientist that at CMCC Foundation who focuses her research on Risk Assessment and Adaptation Strategies.
Furthermore, processes leading to adaptation are far more effective when they are inclusive: involving actors covering different sectors, stages and domains of risks and resilience management to ensure that the needs and perspectives of minority groups are also taken into account.
In this way, different system connections and interdependencies are fully understood.
This is fundamental when talking about coastal planning around the world and not just in Venice.
Moderate future scenarios indicate that by 2050 the homes of 150 million people could find themselves permanently below the high-tide line.
And this is accounting for stability in the Antarctic.
If on the other hand an Antarctic instability outlook is assumed then a total of 300 million people are considered as currently living on land that is at risk.
Since 1880 global mean sea levels have risen by 21-24 cm, with a 3.6 millimetre rise per year between 2006-2015, which is more than twice as much as the average for the rest of the 20th century (1.4 millimetres per year).
As ocean and land temperatures continue to increase scientists are certain that sea levels will continue to rise.
However, the extent of this increment is still up for debate.
One source of uncertainty is the contribution of the Antarctic ice sheet.
The Summary for Policymakers for the Special Report on the Ocean and Cryosphere in a Changing Climate (#SROCC) 🌊 is now available in all UN languages:— IPCC (@IPCC_CH) July 7, 2020
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The reason we are seeing updated figures and at times contrasting predictions has to do with the way in which sea level rise is calculated and the myriad of factors that must be taken into account.
However, to understand where and when sea level rise will impact specific areas and communities scientists must also collect accurate readings of land elevation against which to compare their data.
The most commonly used instrument for evaluating land elevation in the United States is the Shuttle Radar Topography Mission (SRTM).
“I am very sensitive to this issue since I live in a very fragile coastal environment that is highly vulnerable to climate change, the city of Venice and its lagoon”, explains Torresan.The number of vulnerable provinces as well as the magnitude of vulnerability are expected to increase in the future due to the worsening of climate, environmental, and socio-economic conditions.Elisa Furlan, Climate risk, impact and vulnerability assessment scientist at the Euro-Mediterranean Center on Climate Change.
A new paper on risks associated with extreme sea level scenarios in Italy and how both natural and human drivers lead to both risks and vulnerability in coastal areas seeks to provide integrated knowledge and data with information on exposure and vulnerability.
Of particular significance is the paper’s choice to focus on the national scale so as to support policymakers by providing them with a “big vulnerability picture of Italian coasts as a whole and the vulnerability condition of individual coastal provinces.
Results indicate that “the number of vulnerable provinces, as well as the magnitude of vulnerability, are expected to increase in the future due to the worsening of climate, environmental, and socio-economic conditions (e.g. land use variations and increase of the elderly population).”
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