Threat of abrupt climate change
In only a century the atmosphere’s greenhouse gas content has increased by a third causing an unprecedented rate of warming. Today the rate of increase itself is accelerating. Worrying self-reinforcing feedback processes are now underway in the Arctic that climate scientists warn could spiral out of control and spread to the whole planet. Earth’s climate might undergo a step-change in only the next few decades or even years, altering conditions so much that human civilisation as we know it becomes no longer viable. So now scientists and engineers are debating methods of intervening, including reducing atmospheric greenhouse gases, and cooling the Earth’s surface by increasing its albedo (reflecting more sunshine out to space).
Reducing atmospheric greenhouse gases
Carbon dioxide removal (CDR)
Marine Permaculture Arrays
The source of half the Earth’s atmospheric oxygen…
Around half the organic matter in the oceans is comprised of kelp and phytoplankton. Through photosynthesis they produce at least half of the atmosphere’s oxygen, in the process sequestering gigatons of carbon deep into the ocean.
…depends on natural ocean upwellings
What makes oceans productive are upwellings of cold, nutrient-rich water from deep in the sea. Upwellings occur around the world such as in the Grand Banks of Newfoundland—the richest fishing ground in the world—where the icy Labrador Current meets the warm Gulf Stream. This phenomenon is known as overturning circulation.
Overturning circulation under threat
We often think of the ocean as a single fluid entity, but over 90 percent of the heat caused by global warming is absorbed by surface waters. As surface water temperature increases, overturning circulation is thwarted, and upwelling of nutrients decreases or stops altogether. Phytoplankton and seaweed production drops, leading to a decline in the aquatic food chain.
Most of the carbon emitted by human activity is contained within the top five hundred feet of the oceans, causing surface acidification. Reversing this trend is mostly an issue of moving carbon from the near-surface photic zone into the middle and deep ocean. Oceans naturally send carbon from surface water into the depths, a process known as the biological pump.
ocean BIOMASS Declining
Unfortunately, today’s loss of overturning circulation and increased acidification is steadily erasing the marine food chain. Ninety-nine percent of the subtropical and tropical oceans are now largely devoid of marine life. Satellite imagery is detecting a 4 to 8 percent annual decline in biological activity in the Atlantic, a number that exceeds predictions from global warming models. The oceans’ plankton and kelp are estimated to be declining 1 percent annually.
A powerful solution – marine permaculture arrays
Marine permaculture arrays (MPAs) are lightweight latticed structures made of interconnected tubing, to which kelp can attach. They can be tethered near land, or guide themselves autonomously on the open sea. Since they are submerged 25 meters below sea level even the largest cargo ships and oil tankers can pass right over them with no damage, save some shredded kelp. A 0.4 square mile unit would recreate an entire marine ecosystem, akin to reforesting a desert.
How MPAs work…
Marine permaculture recreates the biological pump, enabling oceans to do the job they always have. Buoys attached to the MPAs rise and fall with the waves, powering very simple pumps that bring up colder waters from hundreds or even thousands of feet below sea level. As the nutrient-laden waters come to the sunlit surface, phytoplankton and kelp soak up the nutrients and grow.
…to support thriving ecosystems that sequester CO2.
With phytoplankton come algae, more kelp, and sea grass. These feed populations of herbivorous forage fish, filter feeders, crustaceans, and sea urchins. Carnivorous fish feast on the smaller herbivores, and seals and sea lions and sea otters feed on them. On top of this are seabirds, sharks… and fisher folk. The phytoplankton and kelp that is not consumed dies off and the majority drops into the deep sea, sequestering carbon for centuries in the form of dissolved carbon and carbonates.
This short film describes how marine permaculture arrays could artificially restore overturning circulation:
Bumper HarvestS of fish, FERTILISER and BIO-FUELS
MPAs could host the ultimate fish farms (free-range aquaculture), except the fish would be diverse, wild, untainted, and rich in omega-3 fatty acids.
Kelp harvests would produce abundant fish-feed, fertiliser (including nitrate, phosphate, and potash), and bio-fuels. Each dry ton of kelp sequesters around ton of carbon dioxide.
MPAs in larger groups could seasonally protect coastlines from the worst effects of hurricanes by lowering the surface water temperature, and the latent heat energy upon which hurricanes depend. Given that Hurricane Katrina alone cost $105.7 billion, and 2015 saw twenty-two Category 5 hurricanes, this may be a cost-effective solution. In addition, coral reefs could be seasonally protected from thermally induced bleaching.
ScalEable Costs and benefits
The material costs are currently estimated at $5 million per square km. With a million MPAs active for thirty years, the carbon dioxide drawdown could be over 100 gigatons. The economic return is estimated to exceed $10 trillion. Restored fisheries could supply the protein needs of most of Earth’s 7.5+ billion people.
Today’s demise of living ecosystems needs to be reversed. But perhaps with the implementation of MPAs, human beings can be agents of restoration and increased productivity of fish and kelp forests. Overturning circulation can be restored by deploying marine permaculture arrays, increasing aquatic wildlife, diversity and marine fertility. In addition, bio-fuels and fertiliser can be harvested, and fishing economies and jobs boosted. Most importantly, done at scale MPAs could sequester a large fraction of today’s human caused CO2 emissions permanently into the deep ocean.
More here: Climate Foundation
Buoyant Flake Ocean Fertilisation
Another scalable CDR proposal is very slowly to fertilise barren, sun-drenched areas of the ocean with trace minerals. Floating flakes made from agricultural waste such as rice husks, lignin and mineral tailings are ideal for the job – and cheap. The method has been estimated potentially to sequester 22-47Gt CO2 /year for an estimated $10 per tonne of CO2. At the same time it would also absorb some undersea methane releases, increase ocean albedo, boost fish stocks and restore ocean health generally. Laboratory and ship tank trials with seawater are reportedly going well, with open sea trials off the west coat of India expected to begin in early 2019:
Tech info: Organic Mariculture And Biosequestration
Other Drawdown Technologies
Many other interesting methods for removing atmospheric greenhouse gases are described in Drawdown, a book edited by Paul Hawken, some of which are featured as game changers in Food, Agriculture and Forestry.
Atmospheric Methane reduction
Atmospheric methane can be oxidised a thousand times faster than otherwise, by spraying of a mixture of brine and ferric chloride nano-droplets.
Cooling the planet
Even if atmospheric greenhouse gas removal is scaled up quickly it is unlikely to prevent a major Arctic tipping point being reached. Therefore, direct planetary cooling is now thought to be needed.
Stratospheric Aerosol Injection of sulphates (SAI) appears to be the cheapest, quickest cooling method. However risks include worsening existing droughts and causing new ones, reducing agricultural yields, suppressing forestry growth and damaging the ozone layer. Some scientists worry that further massive intervention may then be needed to correct these side effects. In his book The Madhouse Effect, Climate scientist Prof Michael Mann likens stratospheric sulphate spraying to the children’s song There was an old lady who swallowed a fly, which ends “There was an old lady who swallowed a horse. She’s dead of course.”
On the other hand, the risks of inaction could be even worse. Rising sea levels inundating coastal conurbations around the world, and seasonal loss of irrigation from disappearing mountain glaciers, are both likely to lead to social unrest and increased geopolitical stress, even conflict.
SAI’s main proponent David Keith proposes early testing with very small-scale applications, in order to study and quantify the various effects. Since SAI mimics the release of natural volcanic sulphate release, the effects are known to be temporary. The cooling effects of Mount Pinatubo’s massive eruption in 1991 lasted just two years.
Other deliberate cooling proposals include Marine Cloud Brightening, Polar Ice Thickening and creating plumes of Nanobubbles in the oceans. These proposals are still in their infancy and need further funding for research and development.
The aforementioned Marine Permaculture Array and Buoyant Flake Fertilisation methodologies would also increase ocean albedo, thereby having a cooling effect.
Some people worry that if these methods successfully compensate for carbon intensive economic activity, there will be reduced motivation to rein in greenhouse gas emissions, a condition they describe as ‘moral hazard’. In addition they say it is morally wrong to carry out large-scale experiments on planet Earth.
Need for research
However, having already inadvertently carried out a very dangerous experiment on Earth’s atmosphere, experts are now saying it is time to begin seriously researching the safest methods, to avoid total catastrophe.
Who will pay?
This is a thorny question especially for planetary cooling, because there is no profit to be made, only prevention of bad things happening at indeterminate times in the future. Nation states have evolved mechanisms to fund prevention of future ‘bads’, such as defence budgets. However, the global community has only weak funding mechanisms, such as voluntary pledges. All too often pledges are not honoured.
A recently proposed funding source is the reinsurance industry. It is a globalised industry and will suffer directly as climate impacts become increasingly disastrous. It therefore has has the most direct interest in seeing planetary intervention programs succeed. Funds would be obtained by placing a premium on fossil fuel extraction. Fossil fuel companies would have to pay this premium or be uninsured, and therefore unable to operate.
Of course, this would place a cost on energy which we would all end up paying, and economies would suffer as a result, at least a little. It’s a hard choice. No doubt there would be push-back from the fossil fuel companies and their shareholders. In a way, it’s the same old problem – that mankind has become overly reliant on ‘borrowing from the future’. This proposal will only be successful if it receives sufficient government support. And governments cannot enact policies without sufficient public support.
Careful governance will be needed to ensure that experimentation and any deployment of intervention techniques are safe, fair, effective and economic. The Oxford Principles are an example of a proposed ‘geoengineering governance’ framework.
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