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US government climate report looks at how the oceans are buffering climate change
Posted on 26 December 2017 by John Abraham
In the recently released US Global Change Research Program Report, one of the chapters I was most interested in was about the changes we’ve observed in the world’s oceans. The oceans are really the key to the climate change issue, whether that be in quantifying how fast it’s happening or how much will happen in the future. As humans emit greenhouse gases (particularly carbon dioxide), we see some major changes that cannot be explained naturally.
The oceans are important because they act as a buffer; that is, they absorb much of the effects of greenhouse gases. In fact, the oceans absorb a lot of human carbon pollution. This is a big help for us because without the oceans, the climate would change much faster.
But in a certain way, the oceans are hurting us too. Since the oceans absorb so much of our carbon pollution and the resulting heat (93% of the extra heat), they turn a short-term problem into a long-term problem. Just like a fly wheel can be used to store rotating energy in a machine, the oceans store heat energy and chemical energy that can later manifest itself. The oceans also impact our psychology. The pollution we emit today will have effects for many years (partly because of the oceans). We cannot just stop emitting pollution and think this problem will immediately go away. We have to plan ahead. And, importantly, we have to stop emitting before most of the effects are evident.
I like to think of the Earth’s climate like a heavy train. A train cannot stop quickly; the brakes have to be applied far ahead of an obstacle. The ocean is our “climate train.”
Okay with that, what did this new report show? There were four key findings the authors cited. First, as I mentioned, they report that the oceans are absorbing almost all the heat from greenhouse gases. Over the past six decades, the amount of heat at all levels of the ocean has increased. This heating will continue into the future with approximately 5°F warming by the year 2100. This may not sound like much, but it is really enormous heating for water. When oceans warm, sea levels rise (warming water expands). Warm water also evaporates much faster to the air so that the atmosphere becomes more humid, resulting in more heavy rainfalls and flooding.
The figure below shows the changes in ocean heat (OHC) measured in Joules (a unit of energy).
Ocean heat content data. Illustration: USGCRP report, originally from Cheng et al., 2017
A second conclusion is that the heat may lead to major changes in the ocean currents. There is a really important flow of ocean waters called the Atlantic Meridional Overturning Circulation. It is a stream of water that passes from the warm tropics up toward Europe. Then the water gets cold and dense, sinks, and flows back towards the equator. This current is responsible for the warm wet weather in England, for example (compared with other locations with the same latitude). The report discusses a potential weakening of this current. If the current were to weaken (or stop altogether), there would be major effects to the weather in Europe and North America.
A third conclusion from the report is that the oceans are absorbing a lot of the human carbon pollution. For instance, the oceans currently absorb more than one-quarter of carbon from burning fossil fuels. One consequence of this is the oceans are becoming more acidic. The carbon dioxide is changing the ocean chemistry.
The simple way to think about this is to consider a soda. If you shake a soda and then open the soda, it will fuzz and bubble. This happens because sodas are carbonated beverages. When a soda fizzes, the carbon dioxide is leaving the liquid. What we are doing to the oceans is the reverse process. We are putting carbon dioxide into the ocean waters. Through various chemical processes, it makes the oceans more acidic and that matters for animals that make shells. For many of these animals – particularly those at the base of the food chain – acidic waters can dissolve shells or make them hard to form in the first place. This really matters because if the food chain collapses, then marine ecosystems and human society suffer.
If every city on the coast used heat pumps to extract heat from the ocean and pump it into greenhouses to grow food in (in the deserts and in Arctic regions and so on) it could help a little. Typically one might use 1 unit of energy to move 4 units of heat. Water could be evaporated in greenhouses to humidify air to enhance rainfall. Water could be evaporated in greenhouses to desaleanate it and so on. All this could help move the heat out to space or to grow plants and take carbon dioxide out of the air. Rain moves heat upwards (evaporation at the low side and condensation at the cloud side).
[JH] Sloganeering snipped. Upon further review, initial decision reversed.
Swayseeker: Sorry your comment was axed. No, the scale of civilization, except for CO2 and other carbon related pollution, is relatively small. To act on the scale of the problem requires world wide cooperation at the root of the problem, CO2 emissions.
It is possible to act at the planetary scale, but that requires use of planetary scale tools, such as building tools using the atmosphere itself, which is possible, although we have yet to develop such tools. Solar updraft tower technology begins to work at such a scale, but it is still too small to address the huge scale of ocean heat storage.
However, the atmosphere can engage the oceans' heat as your comment suggests. I like to think in terms of solutions, because if you think only in terms of the problem, as this article shows, is truly awesome, and thus emotionally disabling.
Swayseeker wants to spend billions of dollars to extract maybe 1% of ocean heat content.
Just cut fossil fuel emissions. It's too late to do much about heat already in the system.
Just amplifying my comment. Swayseeker's ideas are interesting and feasible in theory, but look incredibly expensive for what would be achieved. It would cost huge sums obviously just to extract even 1% of ocean heat content given the volumes of heat involved. I would need to see some calculations to be convinced it made sense.
Of course, if some private sector company wants to try such things and sees benefits related to growing crops, then that is their business I suppose.
However it would not be appropriate for governments to spend public money on such schemes. We have three basic options for use of tax payers money1) spend money to reduce emissions and 2) spend money to suck heat out of the system 3) a combination of both
IMO we have to spend all public money money right now on limiting emissions. This is the priority given dangerous climate change scenario. This is economics 101 the best use of scarce resources. I'm talking here particularly about public money and government schemes etc.
If we are successful with limiting dangerous climate change, we can then worry about sucking heat out of the system, if such things are practically plausible.
HadSST3 data shows a +0.613C warming from November 1850 to November 2017 or +0.0367C per decade.
Oct 1850 to Oct 2017 = +0.861C or 0.052C per decade
Sep 1850 to Sep 2017 = +0.835C or 0.050C per decade
Aug 1850 to Aug 2017 = +0.944C or 0.057C per decade
July 1850 to July 2017 = +0.717C or 0.045C per decade
Jun 1850 to Jun 2017 = +0.780C or 0.047C per decade
etc.........
1876 to 1879 HadSST3 data showed an overall GLOBAL ocean warming of almost +0.5C and 13 million Chinese died because of drought and excess atmospheric heat unrelated to CO2 emissions.
Overall atmospheric GLOBAL WARMING is still less than 0.1C per decade over the past 136 years. The recent up-tick is not much different than the 1910s to 1940s warming of 0.7C.
The ocean water is 1000x more dense than the atmosphere. An instantaneous rise of overall ocean temperature of 0.1C can warm the entire atmosphere by 4C almost immediately, because of the added water vapor introduced into the atmosphere. That's simple atmospheric physics and math.
The research report that you refer to is an Obama administration holdover. An extremely biased report.
[DB] Off-topic and sloganeering snipped.
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1911 to 1941 GLOBAL SST was +0.64C while 1941 to 1989 GLOBAL SST was +0.003C. Now we have a 1989 to 2017 GLOBAL SST increase of +0.451C.
Why do we continue to look for heat in the oceans, when our past says we have "NATURAL" warming of the same or higher magnitude on top of the ocean as we did at the turn of the last century?
I should rephrase that : Why do we look for deep ocean heat today, when our current ocean surface warming trend is less than what it was between 1911 and 1941?
Of course the oceans are buffering climate change.
Warming one gallon of atmosphere isn't the same as warming one gallon of ocean water. It doesn't take much to warm a gallon of air by 1C.
How much energy does it take to raise the temperature of 352,670,000,000,000,000,000 gallons of ocean water by 0.1C versus 321,003,271 cubic miles of atmosphere?
Zippi62 @7
"Why do we look for deep ocean heat today, when our current ocean surface warming trend is less than what it was between 1911 and 1941?"
Because the warming since the 1980's is significant and outside the boundaries of natural variation, and evidence shows its driven by CO2 and not natural factors.
The warming period between 1911- 1941 was only 30 years long, so still just within the boundaries of natural variation, so not hugely significant. It was due to a combination of CO2 emissions, high solar activity, and low volcanic activity. The period was a coincidence of multiple factors all at one time, so very non typical.