Rapidly Increasing Global Sea Levels Pose Threat to Coastal Communities, Signaling Potential Disasters
Rewritten Article:
Over the past 2000 years, global sea levels remained relatively steady. That all changed in the 20th century, with a rapid and unabated increase that shows no signs of slowing. Scientists are working overtime to comprehend the implications of this trend, particularly as President Trump slashes funding for agencies tasked with monitoring the oceans.
Since 1993, satellites have provided an unparalleled view into the behavior of our world's oceans.Analysis of this data has been alarming - sea level rise was unexpectedly high last year, and the rate of annual sea level rise has more than doubled over the past three decades, resulting in a 4-inch increase in global sea levels since 1993. This trend is accelerating, as if we're putting our foot on the gas pedal.
These increases spell trouble for the future. Scientists predict that sea levels will rise around 6 inches globally and up to 10 to 12 inches in the US by 2050. However, after 2050, things become murky - "we have such a huge range of uncertainty," Dirk Notz, head of sea ice at the University of Hamburg, told CNN. The world could easily see an extra 3 feet of sea level rise by 2100, but it could also take hundreds of years to reach that level.
Scientists are crystal clear about the cause of this sea level rise: human-caused global warming. Oceans absorb roughly 90% of excess heat, primarily from burning fossil fuels, and as water heats up, it expands. Additionally, heat in the oceans and atmosphere is driving the melting of polar ice caps, particularly the Greenland and Antarctic ice sheets, which together hold enough fresh water to raise global sea levels by around 213 feet. Melting ice sheets have driven roughly two-thirds of longer-term sea level rise, although last year - the hottest on record - ocean warming became the main driver.
Despite this, an increase of about 3 feet may already be locked-in, Notz said, due to humanity's collective impact on the system. The crux of the issue lies in the speed at which these changes will unfold. Ice sheets are the biggest uncertainty, as it's unclear how they will react as the world heats up - whether they'll melt steadily or reach a tipping point and rapidly collapse.
Antarctica, with enough water to raise levels by 190 feet, is often referred to as the "elephant in the room." Notz describes it as an "awakening giant:" It takes a long time to wake up, but once awake, "it's very, very difficult to put it back to sleep." It will take time for scientists to unravel what the future holds for the ice sheets and what that means for sea level rise.
The ocean is not flat like a bathtub, and there are big variations in the way sea level rise is experienced. Coastal regions, such as the US Gulf Coast and Pacific island nations, experience higher rates of rise due to regional currents, erosion, and land shifts caused by natural processes and human activities. The United States coastlines are tracking above global average and toward the upper end of climate model projections, with the Gulf Coast being particularly vulnerable due to oil, gas, and groundwater extraction causing land to sink. Louisiana, in particular, has one of the highest rates of land loss in the world, with some areas experiencing relative sea level rise nearly four times the global rate.
Low-lying Pacific island nations bear the brunt of sea level rise, which already poses a threat to their existence. Over the next three decades, islands such as Tuvalu, Kiribati, and Fiji will experience at least 6 inches of sea level rise even if the world reduces planet-heating emissions, according to NASA.
The world's coastal communities were built with an understanding of where high tides normally reach. "Now we're shifting that normal" and even tiny shifts can cause big impacts, Hamlington said. Already, coastal flooding is increasing, even in the absence of big storms or heavy rainfall. High tide flooding is now happening two to three times more often since 1990 along most US Atlantic and Gulf coastlines.
Sea level rise contributes to coastal erosion and chokes sewage systems, causing salty water to seep into underground freshwater supplies. As the pace of sea level rise accelerates, "it will be very, very difficult to adapt to, because things unfold too quickly," Notz said. Many parts of the world aren't well prepared for these changes, with sea level rise being an "underappreciated" problem as "it's hard to grasp the implications" of even a few inches of rise.
Despite these concerns, humanity still has control over how fast sea level rises over the next decades and centuries by cutting emissions and prioritizing scientific research to monitor the oceans. The global community must address this issue as an ethical responsibility for future generations who will bear the brunt of the consequences.
- The accelerating trend of recent sea level rise, driven by human-caused climate change, has resulted in a 4-inch increase in global sea levels since 1993 and has more than doubled over the past three decades.
- Scientists are predicting that sea levels will rise around 6 inches globally and up to 10 to 12 inches in the US by 2050, but the uncertainty after 2050 is significant, with the world potentially seeing an extra 3 feet of sea level rise by 2100.
- The ocean absorbs 90% of excess heat, primarily from burning fossil fuels, causing it to expand and contribute to sea level rise, while melting ice caps, such as the Greenland and Antarctic ice sheets, are significant contributors to longer-term sea level rise.
- Low-lying Pacific island nations, like Tuvalu, Kiribati, and Fiji, are already experiencing at least 6 inches of sea level rise, with coastal communities around the world, such as the US Gulf Coast, adapting to the increased frequency of coastal flooding due to sea level rise.
- To combat the implications of sea level rise on health-and-wellness, environmental-science, and mental-health, the global community must prioritize scientific research, monitor the oceans, and reduce emissions as an ethical responsibility for future generations.
