13. Warming Oceans
Kerama, 26.186, 127.348
I first snorkeled off the shores of Kerama, a small group of islands in the Okinawa Archipelago in October, 1997. With me were my wife, Susan, and two kids: my son Evan, who was 8 and his nine-year-old friend, Jenna. They were hardy kids and spent most of their time floating in the water, entranced by the colours and astonishing beauty of the coral that stretched in all directions. It was awesome.
There used to be a feeling that when you see something in nature that is beautiful and bright you would be able to return sometime and be thrilled and uplifted again. Not anymore. When I returned to the area a few years later, the framework of the coral was still there, but the life within and the colours were all gone. Instead there was a vast expanse of brown and ghostly white. The devastation had happened in 1998, the year after our visit. A confluence of El Nino and high ocean temperatures caused the largest global coral bleaching ever recorded.
Coral reefs are home to roughly a quarter of the ocean’s 250,000 known species (there are perhaps 2 million unknown species) and are the genesis of much of ocean life. They are also endangered by ocean warming and acidification. The reefs are composed of coral polyps, which build the calcium carbonate structures and zooxanthellae (tiny algae), which provide food. It is the algae that give the coral its rich colors. Although coral is tough it requires water temperatures that do not fluctuate much. When temperatures rise by as little as 1C for one week the polyps expel the algae and the reefs starve, turn white and die.
Until the 1980s incidents of large-scale coral bleaching occurred once every 25 to 30 years. The intervals allowed enough time for recovery. In 1998 parts of the Great Barrier Reef off Australia and other reef systems off Madagascar, Belize and the Maldives bleached. Most recovered, but 15% died. Research from James Cook University found that in the Seychelles 40% of reefs bleached in 1998 have been replaced by weed and algae. This is “regime change” that is likely permanent. Reefs need about 15 years for recovery and only then if protected from pollution and fishing. However, since then there have been so many bleaching events the coral has not had time to recover. The worst happened in 2016 and 2017. The Great Barrier Reef lost half of its corals and 93% of the reef was affected. (Despite this the Queensland government continues to support the expansion of its coal mining industry).
In 2014 the World Resources Institute estimated that 75% of the coral reefs in the Caribbean were in danger, and 95% in South-east Asia. Today the situation would be worse. Baseline sea temperatures have been raised by climate change. Combined with the natural temperature variability that occurs, especially during El Nino events, safe temperature thresholds will be exceeded repeatedly in the future.
Phytoplankton are tiny microscopic plants that form the base of the marine food chain. Every other plant and creature that lives in the ocean depends on them. They grow faster in cold water and slower in warm water. Phytoplankton live in the euphotic zone of the ocean, which is the 80 meter or more strata of the ocean that receives sunlight. They depend on nutrients that come up from lower levels of the ocean, including the bottom benthic zone. In warmer waters this mixing does not take place as effectively, due to density differences between layers, so the planktons receive fewer nutrients. This one feature explains a great danger facing all sea life.
The oceans are getting warmer, caused by massive emissions of greenhouse gases. Effects of this warming have been verified in a NASA-funded study using the OrbView-2 spacecraft, which measured marine biological activity over many years. The effect is greatest in the polar regions. According to a NOAA[1]-sponsored study, in August, 2016 the surface ocean temperatures in the Barents and Chukchi seas, and off both coasts of Greenland, (places I have visited and cherished) were an astonishing 5 degrees Celsius (9 degrees Fahrenheit) above the average for 1982 to 2010. During the summer of 2023 billions of snow crabs vanished in Alaska, likely caused by warm ocean temperatures. The Bering Sea snow crab industry was closed for the first time. In September 2023, scientists found around 100 chum salmon in the Anaktuvuk and Itkillik rivers: never found before. The chum are migrating north as their traditional waters are becoming too warm. This is extreme, but effects are being felt in all regions of the oceans. Hot waters affect mollusks too. Subtidal areas in the eastern Mediterranean, off the coast of Israel, which are some of the fastest warming areas, have been described as deserts, totally devoid of cockles, whelks and other species.
There is natural variability year to year. During El Nino events, when surface ocean temperatures rise, the total heat held by the oceans falls as heat is dissipated into the atmosphere. The opposite happens during El Nina times, when surface temperatures are cooler. Year over year temperatures show a steady increase since pre-industrial times, however. In a recent Chinese study researchers measured temperatures over many parts of the globe for the first 2000 meters of ocean depth. They found that 2017 had by far the highest temperatures. The next highest was 2015, followed by 2016, 2014 and 2013. During 2021 the hottest ever ocean temperatures were recorded, which is the sixth consecutive year that records were broken. The IPCC reports that the oceans have absorbed 90% of the heat caused by man-made emissions. This amounts to 150 times the amount of electricity produced each year and is 60% higher than earlier estimates. During 2023 the average surface ocean temperature reached 21.1C, beating the previous record set in 2016. "The current trajectory looks like it's headed off the charts, smashing previous records," said Prof. Matthew England, of the University of New South Wales.
This warming is not going away. Today global temperatures are about 1 degree C. above those before industrialization began. This is a delayed effect due to the increase in greenhouse gases. Studies indicate that even if all GHGs were to be stopped today the earth will still warm by another .5 deg. C. What does this mean for ocean life? Everything. 25% of sea life is generated on or near coral. This will die off. Warming waters will kill it in the sub tropics and tropics and acidification will cause it to perish in colder zones. It’s already happening on the Great Barrier Reef, in the Caribbean and elsewhere. Warm water holds less oxygen, so anoxia will increase, as will toxic blooms. Mass die-offs and displacement of populations will occur as fish migrate to colder water. Larger fish and predatory mammals such as dolphins and whales will find their food source disappearing. This is already happening along my own coast. In 2021 a "heat dome" settled over B.C. As many as 500 deaths were recorded and temperatures reached 49.6 degrees on June 30 in Lytton. The next day the town burnt to the ground. Along our coast an estimated billion marine animals perished. The stench of rotting shellfish, snails and sea stars was awful where I was paddling off Victoria.
Circulation of deep ocean waters is driven by differences in ocean density, which is affected by temperature and salinity. Hence thermohaline.[2]
Circulation from deep to surface is very slow. It takes about 1,000 years for a drop of water to rise from the deep to the surface and back again. This process is slowed down when surface temperatures rise because temperature gradients are increased. We are left with the uncomfortable conclusion that surface ocean temperatures are going to continue to increase and will stay higher for at least a 1,000 years and probably longer.
In late 2013 a huge patch of warm water started forming in the Gulf of Alaska. During 2014 and 2015 it morphed into an area larger than the continental U.S., stretching from Alaska down to California. A Washington climatologist named it “The Blob”. It fueled a massive outbreak of toxic algae. Thousands of sea lions, sea otters, whales, fish, and birds died due to the toxicity of the algae. Sea lion pups were left starving as their mothers had unhealthy or no food to feed them. It is likely that major schools of salmon were affected, although this would be difficult to determine. Was the Blob caused by climate change? Aided and abetted, probably. It is impossible to know for sure. But, this will be the future of our oceans: bigger storms, rapid change, warmer water, less oxygen, more phosphorous, more acidity, and fewer large fish.
The Intergovernmental Panel on Climate Change (IPCC) met in Paris in 2015. All of the countries in the world agreed that a safe goal would be to limit the rise in global temperatures to 1.5 deg. above pre-industrial times. Since global temperatures have already risen by 1 deg. C. and will warm another .5 degrees due to GHGs already in the atmosphere, this is an almost impossible goal. Experts estimate the possibility of meeting the 2 degrees goal at just 5% — unless carbon is removed from the air. The agreement was voluntary and since then few countries have developed and implemented plausible and enforceable programs to achieve it.
Almost all of the IPCC’s strategies to keep temperature increase below 2 degrees require active carbon capture and storage. This entails scrubbing CO2 from the air and storing it deep underground. Very specific rock formations deep underground are required where there is a porous layer below a non-porous cap.
The best CO2-capturing systems required to neutralize today’s emissions would require roughly 60 million CO2 scrubbers around the world running on an extra 20% of world energy production. This is just removing the CO2 from the air. Most plans require pumping it miles below the surface of the earth and hoping it stays there. There has been little study of the financial and emission costs of manufacturing 60 million sequestering units, 60 million pumps and a few million miles of pipe to shove the CO2 underground and keep it there. Today no government is seriously considering it. Soon it may be too late. (sourced from David MacKay’s remarkably readable: “Sustainable Energy-Without The Hot Air”).
In Canada the federal Liberal government is initiating a comprehensive carbon reduction plan. However, it is also supporting pipeline construction and the expansion of the tar sands, even as major international corporations are retreating from it. Prime Minister Trudeau has stated that no government would leave carbon such as the tar sands in the ground. That is exactly what is required.
No respected independent researchers believe Canada can achieve its CO2 equivalent reduction obligations and grow the tar sands at the same time. Not even close. There is great fanfare, and talk, but no urgency and no action. The Liberal government’s proposal to raise the carbon tax to $170 a tonne by 2030 is a good first step, but unless tar sands emissions are drastically reduced Canada will still fall short of reaching its 2030 emissions-reduction targets.
The story of the world’s largest historical polluter and second greatest current polluter, the U.S., has been an incoherent mess. Coal vs wind and solar. Denial at the very top. At a global conference the U.S. was pushing coal and nuclear power as solutions to the climate emergency. The election of President Biden will change this. If the U.S. becomes a global leader in addressing the climate crisis perhaps we will have a chance at slowing and even reversing some of the worst harm that we are inflicting on this planet. We sure need the U.S. to lead on this.
While the U.S. has been mired in denial and ignorance, China has been publicly trying to assume the role of climate leader. But it currently emits more per person than EU members and is the world’s biggest polluter. It still plans to have its CO2 emissions increase until about 2030, although it may peak earlier. After that, in order to meet its modest reduction objectives, it would have to retire coal power plants at the same rate that it was building them prior to its peak growth phase: 2 to 3 per week. This is unlikely to happen. It is still building more coal plants.
The third biggest contributor historically to climate change is Russia. What is Russia’s biggest and practically only source of export earnings? Oil and gas. Does anyone expect that Russia would willingly cut back? With Russia having invaded Ukraine in late February, 2022, it is more dependent on oil and gas exports than ever. Even India does not condemn Russia's illegal invasion because it is dependent on Russia's fossil fuels. India is a close fourth behind Russia and has now surpassed Russia in annual emissions. It may indeed be the only country of the gang of four to meet its intensity and emissions objectives, but they are very modest. More coal-fired power plants are still planned for both China and India.
The Intergovernmental Panel on Climate Change (IPCC) projected global temperatures to rise between 1.5 deg. C and almost 6 deg. C by 2100. Based on the above and more recent projections by Massachusetts Institute of Technology (MIT), it is almost certain that the rise will be closer to 3 or 4 degrees C. Scientists have stated for a long time that we cannot allow CO2 levels to rise above 400 ppm. Currently we are at 415 ppm and rising fast. CO2 levels haven’t been this high in 20 million years. There is great danger that the climate will pass multiple “tipping points”, leading to a mass extinction scenario midway through this century. IPCC’s own scientists have not accounted for this.
So, we have only 10% of large fish stocks left compared to pre-industrial times and ocean conditions are getting worse. What are we to do? There is only one answer. We double down on conservation and try to increase stocks while actively reducing our own GHG emissions. As Callum Roberts states, “we need to protect and increase diversity and abundance.”
An April, 2023 study by the US National Oceanic and Atmospheric Administration (NOAA) found temperatures gathered by satellites and buoys have broken fresh records and reached "uncharted territory". With an El Nino weather event expected this year temperatures are likely to rise even higher.
[1] National Oceanic and Atmospheric Administration, U.S. Department of Commerce
[2] Cold water, in general, is denser than warm water. Likewise, water with a high salinity is denser than water that contains less salt. Surface ocean currents are primarily driven by winds. Deep ocean currents, on the other hand, are mainly a result of density differences. The thermohaline circulation often referred to as the ocean’s “conveyor belt”, links major surface and deep water currents in the Atlantic, Indian, Pacific, and Southern Oceans. (https://scied.ucar.edu/ocean-move-thermohaline-circulation)
