Scientists have found that 269 airports are at risk of coastal flooding now. A temperature rise of 2C – consistent with the Paris Agreement – would lead to 100 airports being below mean sea level and 364 airports at risk of flooding. If global mean temperature rise exceeds this then as many as 572 airports will be at risk by 2100, leading to major disruptions without appropriate adaptation.
Low-lying atolls in the Pacific Ocean have long been considered some of the most vulnerable areas to climate change, as rising sea levels threaten to submerge them.
But over the past decade, scientists have noted a puzzling phenomenon: some islands are getting bigger.
A joint U.S.-European satellite, built to monitor global sea levels, lifted off on a SpaceX Falcon 9 rocket from Vandenberg Air Force Base just after 9 a.m. Pacific Time on November 21, 2020. About the size of a small pickup truck, Sentinel-6 Michael Freilich will extend a nearly 30-year continuous dataset on sea surface height.
As seas rise and coastal storms intensify, policymakers and low-lying cities around the globe are increasingly wrestling with the reality of needing to relocate entire communities to higher, safer ground. Scientists estimate that up to 340 million people in coastal areas could be displaced by 2050, and 630 million by 2100, in locations from the United States to Nigeria to the Philippines.
The Sentinel-6 will see details that previous sea level missions couldn’t. Existing satellites can track large phenomena stretching thousands of miles, such as the Gulf Stream and weather patterns like El Niño and La Niña. But smaller sea-level fluctuations near coastlines exceed their abilities. Sentinel-6’s higher resolution measurements will enable researchers to see finer, more complicated ocean features, especially near shorelines. It will also offer faster data turnarounds—collecting, processing, and releasing data within three hours, down from months and years. The data can be used to more quickly and accurately predict, map, and 3D model coastline changes; weather, such as hurricane intensity; ocean current fluctuations, which dissipate climate energy; and ocean topography and circulation, as movement of heat, salt, pollution, and nutrients impacts marine ecosystems.
Ask climate scientists how fast the world’s oceans are creeping upward, and many will say 3.2 millimeters per year—a figure enshrined in the last Intergovernmental Panel on Climate Change report, from 2014. But the number, based on satellite measurements taken since the early 1990s, is a long-term average. In fact, the global rate varied so much over that period that it was hard to say whether it was holding steady or accelerating.
Five years after causing anger and anxiety in Christchurch’s coastal communities, the council is taking a new approach to tackle the impact of rising sea levels. Christchurch City Council is embarking on a lengthy process to figure out how its low-lying coastal and inland communities will adapt to the ramifications of climate change.
Global trade and transport depend on the resilience of the ports sector. Multi-hazard operational risks are estimated for 2,013 ports under historical climate and future warming; of the marine and atmospheric hazards considered, coastal flooding, wave overtopping and heat stress increase risk most.
The Sentinel-6 will use radar altimetry to obtain near real-time measurements of sea surface height and wind speeds, which will help scientists monitor sea level rise. The mission is a collaboration between ESA, the European Commission, EUMETSAT, NASA and NOAA, with support from the French space agency CNES.
