Many scientists around the world are currently dealing with an unusual anomaly. The water in the Atlantic is significantly warmer than it should be. So far, however, no one has found a reasonable explanation for this – there are assumptions, but nothing more.1 In general, the water temperature of the oceans is also significantly above the long-term average temperatures this year, as the following graph shows.
Daily global average ocean water temperature over the past 20 years; Source: climatereanalyser.org, Climate Change Institute, University of Maine
However, the next graph makes it clear that this is not a unique phenomenon. If you take the records of the years 1981-2000 out of the analysis, the temperatures have been exclusively (significantly) above the long-term average for 22 years. Since 2015, temperatures have even been consistently above the upper average temperature.
Daily global average air temperature over the past 40 years; Source: climatereanalyser.org, Climate Change Institute, University of Maine
Effects of the increased water temperature
But what does the – comparatively – enormous increase in water temperature mean? A fish kill is currently being observed in the North Atlantic in particular. Since June of this year, for example, more than 10,000 dead fish have washed ashore in Texas. The rise in temperature causes the oxygen content of the water to drop, which is why the fish eventually suffocate.
However, the NOAA (National Oceanic and Atmospheric Administration) reports that fish deaths are not new.2 Basically, this happens every year due to the sewage that is washed into the Gulf of Mexico through the Mississippi River. However, as nitrate and phosphorus pollution from agriculture in the US has decreased in recent years, the so-called dead zone should normally decrease. However, the warming of the oceans could have a counterproductive effect and the fish kill could continue or even increase in this dimension.
Warmest day worldwide so far
In terms of air temperature, June was also the warmest day since records began – worldwide. If we leave the years 1979-2012 out of the equation, here too we are exclusively above the long-term average – in many parts even significantly above it. This problem is a separate topic in itself, but should be mentioned here.
Daily global average air temperature over the past 40 years; Source: climatereanalyser.org, Climate Change Institute, University of Maine
Conclusion
A comparison of the temperatures of the last 10 years with those of the last 40 years shows that global warming is clearly picking up speed – whether we like it or not. The fish kill in Texas once again shows the serious consequences of the climate crisis and highlights the importance of investments to preserve biodiversity and protect ecosystems.
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1 Warum erwärmt sich der Nordatlantik so stark? | tagesschau.de