ROYAL SEA RESEARCH INSTITUTE
In an effort to provide decision-makers with insight into the consequences of climate change, climate researchers at NIOZ, Deltares and UU are producing a large number of sea-level projections, translate climate models to projected sea level rise. Their new review was published in the scientific journal Earth’s Future. “These results provide tools for short- and long-term decision-making.”
Aimée Slangen is a climate scientist at NIOZ and co-author of the IPCC climate report. Together with climate adaptation experts Marjolijn Haasnoot and Gundula Winter from the Universities of Deltares and Utrecht, both authors of the IPCC, Slangen investigated the similarities and differences between many sea-level projections published in recent years.
Eight families
“We found that the set of more than 80 different forecasts could be reduced to eight ‘families’. “In each of the forecasting groups we identified, the researchers often used similar data, but they used different modeling approaches, for example. As a result, each new publication leads to different projected sea-level rise, depending on whether the publication focuses on the short or long term, or on the models used to estimate the impacts. process that causes a potentially large contributor to the rapid melting of Antarctic ice. ”
These details are interesting to scientists, but make it more difficult for users to maintain an overview. Slangen: “This can be a problem when you have to decide as a government what you are going to do to protect your coast from rising sea levels. Decision makers cannot adjust their policies with each new publication. ”
Increase by half a meter before the end of this century
The researchers hope to clear this doubt, as all families paint a similar picture of the first 50cm sea level rise. Slangen: “We will see the first half-meter increase before the end of this century, even as we begin to reduce greenhouse gas emissions on a large scale. Therefore, for this period, what you use to forecast sea level is no different from what your household uses. “
So that means we can start adapting to the consequences of sea level rise now, says adaptation expert Haasnoot. “Those who have to make climate adaptation decisions can already get started. However, it is important to account for the uncertainty of the future. If you plan wisely, you ensure that what you are doing now for half a meter sea level rise can be adjusted later for one meter. That will save a lot of money and effort.”
Emissions models and scenarios
The greater the sea level rise, the more diverse the eight families become. Slangen: “From 75 centimeters to one meter of sea level rise, it’s more important what modeling approach you use and what climate scenario you follow. While such larger values are only exceeded in the long term, they can inform adaptive decision making already in the medium term. Every family is valuable to a particular situation, and certain threshold values are exceeded at times.”
Haasnoot: “In a vulnerable area, for example, you might choose a family with a large acceleration in Antarctic melting. Many of the world’s major cities, such as London, New Orleans and Rotterdam, are located in vulnerable areas. In such large deltas, relative sea levels rise even faster due to land subsidence, such as from groundwater extraction. “
diagram
In their publication, the authors present a diagram that policymakers can use when deciding when and how to make adjustments, while taking into account the range of uncertainty in their forecasts. seawater. “For example, the timing of these sea level values can be used to estimate how long a measure is still effective,” says Haasnoot. But the opposite: given a desired lifetime, you can use these values to design a protection.
Slangen: “For the first 25cm sea level rise, the bandwidth of time is small: projections suggest this will happen before 2060. A half-meter rise will be reached before the end of the century. The greater the sea level rise, the greater the uncertainty. Depending on the family, elevations of 1.5 to 2 meters could be reached by 2100, but it could also be 2200 or later.”
DOI
RESEARCH METHODS
Data analysis / statistics
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Rethinking sea level projections using home and time differences
ARTICLE PUBLICATION DATE
March 30, 2022
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