Argo Floaters are technological wonders.
Each one, when set, sinks to 1000 meters below the ocean surface where it drifts with the current for 9 days. On day 10 it sinks to 2000 meters, then over a 6 hour period it rises to the surface, recording temperature and salinity. When it reaches the surface, it signals its position to a GPS satellite, and it transmits its data to a data bank. Then it sinks again to 1000 meters to start the cycle over again.
Since the Argo project started, funded by NOAA, in 2000, more than 3500 floaters have now been set, about 300 km apart, with 30 countries participating. The US has set about half of them, but Canada has set almost 400, and China nearly 200. They now produce about 120,000 temperature and salinity profiles from all parts of the ice-free oceans each year.
It gets better. That transmitted data uploaded to a data bank is made available to internet users around the world within the next 24 hours, providing an almost real-time view of ocean temperatures and salinity down to 2000 meters.
We have been measuring ocean temperature and salinity at many depths and many places for decades, but never like this. With so much data, uncertainty decreases, and a detailed picture of the climate of the oceans emerges. We are documenting in remarkable detail the heat accumulating in the ocean and how it is transferred within the ocean on local, seasonal, annual and now decade scales.
The graphs are unequivocal, updated almost daily, there for all to see.
A recent commentary in Nature emphasizes that no one indicator of global climate change is sufficient. Just as the measurement of multiple vital signs give a clearer sense of a human’s health, so multiple indicators give us an increasingly clear image of the planet’s climate change. We have relied a lot on the calculation of the global average surface temperature of our atmosphere, which is variable in every way imaginable. Other indicators are greenhouse gas emissions and concentrations, high-latitude temperatures, and sea level rise.
And now we also have the finest data we could hope for, measuring the relentless increase in the heat of the oceans. Oceans absorb 93% of the extra energy being added to the climate system, in turn heating the atmosphere. The rising levels of ocean heat is our best indication – and warning – of the long-term global warming that has just begun.
We may be documenting global warming with increasing accuracy and confidence, but denial by powerful politicians remains an immense obstacle to action. For instance if the Republican Party wins the US Senate in next week’s election, Senator Inhofe is in line to Chair the Committee on Environment. He’s the one who wrote the book about global warming called The Greatest Hoax
Meanwhile, school programs scattered around the US are following the Argo project, learning about the rising heat content of the oceans, even adopting Argo Floaters.