What would you like to know?

Answer

marine heatwaves

One practical consequence of rising ocean heat content is a greater frequency and intensity of marine heatwaves — prolonged periods of anomalously warm water in a given region. These events have been linked to coral bleaching, shifts in fish populations and disruption to marine food webs, and researchers have documented an increase in their frequency, duration and geographic extent over recent decades. It is worth being precise here: attributing any single heatwave entirely to long-term ocean warming, as opposed to a combination of that warming and shorter-term regional weather patterns, generally requires dedicated attribution analysis rather than a straightforward reading of the temperature record alone.

• The upper ocean (roughly the top 700 metres) has warmed measurably across every ocean basin monitored.
• Deeper ocean layers are also absorbing heat, though the signal there is smaller and takes longer to detect with confidence.
• Because the trend is driven by long-term energy accumulation rather than short-term weather variability, it has shown fewer of the flat or cooling years sometimes seen in surface records.
• Warmer ocean water expands in volume, making thermal expansion one of the largest contributors to observed sea level rise, alongside land ice melt.