Lasers are painting a clear picture of the rising sea levels we face today. A recent study reveals that global mean sea level (GMSL) has risen about 3.5 inches since 1993. Alarmingly, this rise is accelerating, particularly over the last two decades.
Most of the increase—around 60%—comes from added water, primarily due to melting land ice. As the oceans absorb about 90% of the extra heat trapped by greenhouse gases, this process is only speeding up.
Dr. Yufeng Nie from the Hong Kong Polytechnic University led a study using satellite laser ranging (SLR) technology. This method measures the distance to satellites with exceptional accuracy. By firing laser pulses and tracking their return, researchers can detect minute changes in Earth’s gravity caused by shifts in water and ice. This precise data allows scientists to monitor how much new water is flowing into oceans.
A comparison of laser data with the GRACE satellite mission, which started tracking Earth’s water in 2002, shows consistent findings. This alignment boosts confidence in our understanding of sea level rise.
The SLR technique is crucial for filling data gaps. While GRACE has its limitations, the laser measurements extend back to the early 1990s, providing a more complete picture of how ocean mass is changing. This technique cross-checks satellite altimetry, which measures sea surface height, reinforcing the integrity of these measurements.
You might think 3.5 inches isn’t much, but this extra height adds up. Places near coastlines are already experiencing more frequent flooding, as higher tides now push water onto streets that used to remain dry. Heavy rainfall and storm surges exacerbate this situation, leading to flooding reaching further inland than ever before.
Recent data shows that communities on low-lying coasts face increased risks due to rising sea levels. The rates of change are uneven around the globe, meaning some areas feel the impact sooner than others. Dr. Nie emphasizes that understanding these shifts is vital for city planners who need to prepare for a changing environment.
Scientists aren’t just sitting idle; they are closely monitoring the future. With long records from laser technology, they can compare actual measurements with climate models to see if predictions about sea level rise hold true.
The tools we have for understanding these changes are improving. Lasers provide stability over decades, while GRACE missions track mass shifts month-to-month. Combining these technologies enhances our ability to predict coastal impacts.
In summary, rising sea levels are making it increasingly essential for communities to prepare for change. Whether it’s elevating infrastructure, enhancing natural buffers, or planning around new flood risks, the choices made today will have lasting effects. Consistent and accurate measurements can help keep uncertainties at bay and guide communities in managing the realities of a changing climate.
For further insights, you can check the detailed findings published in the Proceedings of the National Academy of Sciences here.
This growing issue is a reminder of the importance of adapting to our changing world.
