In our warming world, extreme coastal flooding events are occurring more frequently than ever before, threatening countless communities who will become even more vulnerable. Climate change Is intense.
A recent study found that Once in a century flood events Now our planet is attacked about once in a decade. The study, published June 10 in the journal nature climate changeIt also found that human-driven climate change has quadrupled the frequency of coastal sea level extremes since 1900.
The findings were released alongside another study by a separate team, published in the journal science advancementWhich found that human-caused sea level rise was clearly measurable at 97% of sites sampled around the world, and accounted for about 58% of the daily extreme water levels observed between 2000 and 2018. In other words, human activities are the primary driver behind sea level extremes – including storm surges, high tides and rising sea level anomalies.
As seas grow increasingly powerful with the potential to devastate coastal communities, Live Science spoke to Sonke DangendorfLead author of the Nature Climate Change study to learn more about what’s to come. Here’s what he had to say.
Dangendorff is the David and Jane Flowery Associate Professor in the Department of Riparian Science and Engineering at Tulane University.
Patrick Pester: How do you separate human-driven sea level rise from natural forces?
Sonke Dangendorf: The whole premise of doing this type of investigation is to work with observations, but unfortunately observations are sparse. We have over 100 tide gauges [distributed worldwide] Which present long, century-scale records of sea level change since the beginning of the 20th century. We see that sea levels are changing in those places, but we can’t completely tell what’s happening elsewhere. Therefore, we can use the same climate models that we use to produce future projections of sea level change.
If you compare observations with models, the models should be able to reproduce what the observations have shown. That was the first step that we took, and really what we proved in this study is that climate models are able to reproduce the observed climate. The nice thing with climate models is that if you are able to reproduce what is observed, you can start experimenting. For example, you can put green house gases Model consistency and then assess the impact of natural climate variability on the changes we observe. That’s what we did in the study.
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We found that globally we have already seen an average 12-fold increase in the once-in-100-year incidence since 1900. And when we do these forced experiments, we also see that anthropogenic coercion [human-driven change]Especially since the 1970s, has become the dominant power.
PP: What does this mean for coastal communities around the world?
sd: A few centimeters of sea level rise may not sound like much in theory, but if you live along the coast, it has a more profound impact on you than you might imagine. Just one example: I lived on the American East Coast in Norfolk, Virginia. The community was built along the water, and they used to be fine in the 1950s and 1960s; They may not see floods at all, or perhaps once every five or six years. But due to rising sea levels, what now happens is that high tides cause floods. You see roads filled with water, and that affects your commute, so people can’t get to work.
It affects your daily life suddenly. And then it makes it much harder for you and your coastal community because your insurance costs are going up – the cumulative cost of these events can easily be as much as a major hurricane makes landfall. So, this is a daily experience that many people already have, and it is a direct impact of sea level rise.
In relation to what we estimated in these more extreme events, people can absorb a once in 100 years event in their lifetime. They may experience something like this hurricane sandyAnd they may be able to recover from it, but if you think about basically recovering from it every eight years – the frequency of these events nowadays compared to 1900 – it’s certainly much more difficult and not possible for many people.
PP: What can we do?
sd: We can adapt. The silver lining here is that we have shown that humans are the major driving factor behind these changes. This is a ray of hope because it means that if we react, we can do something about it.
Responses to climate change are often delayed, so we have sea level rise to which we are already committed. For example, if you look at the projections, they all agree on what will happen by around 2060, regardless of how much greenhouse gas is emitted. There is no way around that. We could stop emitting greenhouse gases today, and we would still experience it. So, we need to adapt to sea level rise, but if we mitigate climate change, if we stop emitting greenhouse gases, we can avoid dangerous sea level rise, and that’s very important.
As our planet warms, floods are becoming more severe and disruptive.
(Image credit: Roberto Westbrook via Getty Images)
PP: What will the world look like in 2060 with committed sea level rise?
sd: as per last ipcc [Intergovernmental Panel on Climate Change] reportWhat previously was a once-in-100-year phenomenon will occur annually at 19% to 31% of tide gauge locations today by 2050. So, in about a quarter of the places, you’ll experience these once-in-100-year events annually, and that’s something that’s pretty amazing.
Changes are occurring much more rapidly in low-latitude locations. This is because the climate is generally less variable in the tropics. You don’t have such massive fluctuations all the time. For example, in the North Sea, we have a hurricane season, and we have huge tide ranges. We are already adapted to large-scale changes of several meters, so a sea level rise of a few centimeters is not so difficult, but in the tropics, where it is much cooler, it makes a big difference.
As an analogy, think of two hurdlers. You have a hurdler who has been compared to the tropics; He jumps very constantly but always below the obstacle, so he never gets over it. Then you have another hurdler who is a North Sea type of guy. His jumps are very variable. Sometimes he is too high and jumps over that obstacle, but often he also jumps too low. Now think about mitigating that disruption, which is equivalent to sea level rise. Suddenly, the hurdle runner who is very consistent gets over it all the time, whereas the guy from the North Sea may jump the hurdle a couple more times, but he still has very low standards. Therefore, the constant jumper is more sensitive to these changes.
Editor’s note: This interview has been edited and condensed for clarity.