Warmest seas on record
Global ocean temperatures are set to break the all-time record this year, scientists warn. Data from monitoring agencies shows sea surface temperatures running above every previous year at the same point in the calendar. The trend follows two years of record ocean heat.
Oceans absorb most of the extra heat trapped by greenhouse gases. That makes sea surface temperature one of the clearest signals of climate change. The current readings point to another year of marine heatwaves in many regions.
What warmer oceans mean
Hotter seas fuel stronger storms. Hurricanes and typhoons draw energy from warm surface water, so record ocean heat raises the risk of intense cyclones this season. Coral reefs also suffer when water stays warm for long periods, triggering bleaching events that can kill reefs.
Fisheries and coastal communities feel the effects first. Fish species move toward cooler waters, disrupting catches and local economies. Marine heatwaves have already caused mass die-offs of seabirds and marine mammals in recent years.
Looking ahead
Scientists say ocean heat will keep rising until emissions fall sharply. Short-term natural cycles can push temperatures up or down, but the long-term warming trend continues. Researchers are watching for signs that the oceans may be losing some ability to absorb heat.
Climate models project more record years ahead. Scientists call for faster cuts in fossil fuel use and more investment in adapting coastal regions. The ocean's heat content, they note, is a measure of how much work remains.
The record comes with a human cost. Coastal cities face more flooding as warm water expands and glaciers melt into the sea. Insurance costs are climbing in exposed regions, and some communities are already planning retreat from the shoreline. Marine industries, from tourism to shipping, are adjusting schedules and routes to cope with changing conditions.
Monitoring agencies will release their final rankings at the end of the year. Whether this year sets a new high or falls just short, the past decade has delivered the warmest oceans ever measured. Scientists say the direction is clear, and the pace depends on how quickly the world cuts emissions.