It is the relentless pounding of these waves and the angle or direction of incoming wave energy that will determine our future coasts, so quickly expanding our understanding of current and future patterns in wave energy is critical for coastal management and decision making.
Recently, we have been able to show that wave energy has been changing throughout the last six decades. After comparing the differences in wave energy throughout the decades, we found that there was more energy in waves in many regions from the 90s and 00s as compared to the 80s (see map below). Indeed, the wave energy has been increasing greatly across nearly the entire Southern Ocean covering most of the coasts of South America, Africa, Australia and Micronesia. The pattern is more complex in the northern hemisphere with Europe and the U.S. West coast seeing less wave energy, but the U.S.-East and Caribbean seeming somewhat more wave energy.
Overall there are significant increases in wave energy and this affects many of the most at risk large cities and vulnerable small island states alike. Moreover wave energy can increase greatly from more regular climatic events. For example, with an upcoming El Niño season, we can expect wave energy to increase in many areas across the Pacific Ocean. Here in California, we are hoping El Niño brings much needed rain (and the surfers hope for fun waves); we have forgotten for a moment the images of cliffside erosion and homes falling in to the water as they succumb to the erosion from these waves and wind.
Waves are powerful and their effects are easily observable on our coasts. As wave energy increases, these effects will be more profound. Most of our coastal structures were designed and permitted to withstand a very particular amount and direction of wave attack. Flooding and erosion will accelerate. Our coastal defense structures will fail more often and more spectacularly.
This will be bad news overall, but at least these climate change problems will be highly observable (even photogenic) and should motivate action from decision-makers. We need to quickly and better understand these changes. Our assessments of risk and where we build based on this risk must be updated. Our future structures must be designed to withstand these changing forces. By furthering the research in wave action and refining future wave projections, we can determine what’s in store for our coasts in an era that will also include rising seas and chart the best possible course to protect our coastal communities.
Dr. Borja G. Reguero is a postdoctoral fellow for The Nature Conservancy. Dr. Michael W. Beck is the lead marine scientist for The Nature Conservancy.