The next stage of humanity’s fight to reduce greenhouse emissions may revolve around seaweed, according to tonight’s episode of ABC’s Catalyst, presented by Professor Tim Flannery, which asks the question “can seaweed save the world?”
With the help of me and colleagues around the world, the documentary explores seaweed’s enormous potential to reduce greenhouse gases and draw CO₂ out of the atmosphere. In the case of seaweed, that could include giant kelp farms that de-acidify oceans, or feeding algae to cattle and sheep to dramatically reduce their methane emissions.
But while these possibilities are exciting, early adopters are dealing with unproven technology and complex international treaties. Globally, emissions are likely to keep rising, which means seaweed-related carbon capture should only be one part of a bigger emissions reduction picture.
Net negative emissions
To stay within the Paris climate agreement’s 2℃ warming threshold, most experts agree that we must remove carbon from the atmosphere as well as reduce emissions. Many scientists now argue that 2℃ will still cause dangerous climate change, and an upper limit of 1.5℃ warming by 2100 is much safer.
To achieve that goal, humanity must begin reducing global emissions from 2020 (in less time than it takes an undergrad enrolling now to finish their degree) and rapidly decarbonise to zero net emissions by 2050.
Zero net carbon emissions can come from radical emissions reductions, and massive geoengineering projects. But it could be vastly helped by what Flannery calls “the third way”: mimicking or strengthening Earth’s own methods of carbon capture.
On the other hand, seaweed solutions could be put to work in the biologically desert-like “doldrums” of the ocean, and have positive side effects such as helping to clear up the giant ocean rubbish patches. However, there are many technical problems still to be solved to make this a reality.
We probably haven’t reached peak emissions
Removing carbon from the atmosphere is an attractive proposition, but we can’t ignore the emissions we’re currently pumping out. For any negative emissions technology to work, our global emissions from fossil fuels must start to drop significantly, and very soon.
But wait a second, haven’t we already hit peak emissions? It’s true that for the third year in a row, global carbon dioxide emissions from fossil fuels and industry have barely grown, while the global economy has continued to grow strongly.
This is great news, but the slowdown in emissions growth has been driven primarily by China, alongside the United States, and a general decline of emissions in developed countries.
China’s reductions are impressive. The country peaked in coal consumption in 2014, and tends to under-promise and over-deliver on emissions reductions. However, under the Paris agreement, China has committed to a 60-65% reduction in emissions intensity, which means there’s still room for them to rise in the future.
India’s emissions, on the other hand, are major wild card. With a population of 1.3 billion and rising, about 300 million of whom are still not connected to an electrical grid, and potential increases in coal use to provide energy, India will be vital to stabilising greenhouse gases.
India’s emissions today match those of China in 1990. A study that combined India’s Paris agreement targets with OECD estimates about its long-term economic growth, suggested India’s CO₂ emissions could still grow significantly by 2030 (although per capita emissions would still be well below China and the US).
The emissions reduction relay race
So how do we deal with many competing and interconnected issues? Ideally, we need an array of solutions, with complementary waves of technology handling different problems.
Clearly the first wave, the clean energy transition, is well under way. Solar installations are breaking records, with an extra 75 gigawatts added to our global capacity in 2016, up from 51 gigawatts installed in 2015. But this still represents just 1.8% of total global electricity demand.
In addition to renewable energy generation, limiting warming to below 1.5°C also means we must increase the efficiency of our existing grid. Fortunately, early-stage financiers and entrepreneurs are focusing on a second wave of smart energy, which includes efficiency and optimisation technologies. Others in Australia have also noted the opportunities offered by the increasing use of using small, smart devices connected to the internet that respond to user demand.
Although early user results have been mixed, research shows better system control reduces the emissions intensity of energy generation. These energy efficient devices and optimisation software are on the cusp of becoming widely commercially available.
Critically, these efficiency technologies will be needed to complement structural change in the fossil fuel energy mix. This is especially in places where emissions are set to grow significantly, like India. Building renewable energy capacity, optimising with new software and technologies, and better understanding the opportunity for net negative emissions all play an important part in the emissions reductions relay race over the next 50 years to get us to 1.5°C.
With further research, development, and commercialisation, the possibilities offered by seaweed – outlined in more detail in the Catalyst documentary – are potentially game-changing.
But, as we saw with the development of renewable energy generation technology, it takes a long time to move from a good idea to wide implementation. We must support the scientists and entrepreneurs exploring zero-carbon innovations – and see if seaweed really can save the world.
Can Seaweed Save the World? airs on the ABC on Tuesday 22 August at 8.30pm.
Cement is the world’s most widely used material apart from water, largely because it is the key ingredient in concrete, the world’s favourite building material.
But with cement’s success comes a huge amount of greenhouse emissions. For every tonne of cement produced in Australia, 0.82 tonnes of CO₂ is released. That might not sound like much, especially when compared with the 1.8 tonnes emitted in making a tonne of steel. But with a global production of more than 4 billion tonnes a year, cement accounts for 5% of the world’s industrial and energy greenhouse emissions.
Read more: The problem with reinforced concrete.
The electricity and heat demands of cement production are responsible for around 50% the CO₂ emissions. But the other 50% comes from the process of “calcination” – a crucial step in cement manufacture in which limestone (calcium carbonate) is heated to transform it into quicklime (calcium oxide), giving off CO₂ in the process.
A report published by Beyond Zero Emissions (BZE) (on which I was a consultant) outlines several ways in which the sector can improve this situation, and perhaps even one day create a zero-carbon cement industry.
The cement industry has already begun to reduce its footprint by improving equipment and reducing energy use. But energy efficiency can only get us so far because the chemical process itself emits so much CO₂. Not many cement firms are prepared to cut their production to reduce emissions, so they will have to embrace less carbon-intensive recipes instead.
The BZE report calculates that 50% of the conventional concrete used in construction can be replaced with another kind, called geopolymer concrete. This contains cement made from other products rather than limestone, such as fly ash, slag or clay.
Making this transition would be relatively easy in Australia, which has more than 400 million tonnes of fly ash readily available as stockpiled waste from the coal industry, which represents already about 20 years of stocks.
These types of concrete are readily available in Australia, although they are not widely used because they have not been included in supply chains, and large construction firms have not yet put their faith in them.
Another option more widely known by construction firm is to use the so-called “high blend” cements containing a mixture of slag, fly ash and other compounds blended with cement. These blends have been used in concrete structures all over the world, such as the BAPS Shri Swaminarayan Mandir Hindu temple in Chicago, the foundation slab of which contains 65% fly ash cement. These blends are available everywhere in Australia but their usage is not as high as it should due to the lack of trust from the industry.
It is even theoretically possible to create “carbon-negative cement”, made with magnesium oxide in place of traditional quicklime. This compound can absorb CO₂ from the air when water is added to the cement powder, and its developer Novacem, a spinoff from Imperial College London, claimed a tonne of its cement had a “negative footprint” of 0.6 tonnes of CO₂. But almost a decade later, carbon-negative cement has not caught on.
The CO₂ released during cement fabrication could also potentially be recaptured in a process called mineral carbonation, which works on a similar principle as the carbon capture and storage often discussed in relation to coal-fired electricity generation.
This technique can theoretically prevent 90% of cement kiln emissions from escaping to the atmosphere. The necessary rocks (olivine or serpentine) are found in Australia, especially in the New England area of New South Wales, and the technique has been demonstrated in the laboratory, but has not yet been put in place at commercial scale, although several companies around the world are currently working on it.
Yet another approach would be to adapt the design of our buildings, bridges and other structures so they use less concrete. Besides using the high-performance concretes, we could also replace some of the concrete with other, less emissions-intensive materials such as timber.
Previously, high greenhouse emissions were locked into the cement industry because of the way it is made. But the industry now has a range of tools in hand to start reducing its greenhouse footprint. With the world having agreed in Paris to try and limit global warming to no more than 2℃, every sector of industry needs to do its part.
Wildebeest rarely stay still for long. With sloping hindquarters, and an easy loping gait, their bodies are designed to move. In the Serengeti ecosystem, for instance, a wildebeest will move over more than 2,000 kilometres during their annual migration.
Migratory or nomadic animals, like wildebeest, that live in drylands need to move over vast distances to find sufficient water and nutrients. They follow localised and variable rainfall and food resources.
The Serengeti wildebeest spends the wet season, November to April, on the short grass plains of the southern Serengeti National Park and adjoining Ngorongoro Conservation area in Tanzania. Here they feed on nutritious grass shoots that grow in response to the abundant rain. But even here, they do not stay still. They constantly move across the short grass plains in search of the fresh grass that grows after each new rainfall. This allows mothers to maximise milk production for their calves, born during a simultaneous calving of more than a quarter a million, peaking in February.
When the rains cease at the end of April, the wildebeest start their long journey to their dry season grazing areas. They first move west, and then head north, following the remaining water in the rivers before moving on as they dry out. Eventually they reach the only permanent water found in the Mara River on the Kenyan border. The dry season is hard, and many wildebeest die of starvation during this period.
When the rains start in November, the wildebeest lope down south once again. They make the journey to the short grasslands nearly 200km away in just a few days. Here they graze, recover their strength and the cycle begins again.
If these Serengeti wildebeest were to face a barrier at any point in their journey, they would die, either of starvation or thirst. Sadly, this has happened to migratory animals elsewhere in Africa. For example, over 30 years ago, after a fence was erected as a veterinary cordon to separate wildlife from cattle in the Kalahari, 80,000 wildebeest and 10,000 hartebeest died when they were no longer able to access permanent water during a drought. The fence was built to satisfy European Union livestock disease regulations, and allow southern African countries to export meat into the European Union.
Unfortunately, the ability of wildlife in Africa to continue to move across landscapes is still being threatened by linear barriers, and this is particularly a problem in Africa’s drylands.
African drylands are home to most of its large mammal species. These include semi-arid and arid savannahs, found across much of eastern and southern Africa, which support spectacular wildlife migrations, such as those found in the Serengeti. But drylands also include hyperarid deserts, such as the vast Sahara, home to distinctive nomadic species such as the critically endangered Addax and dama gazelle.
Because mobility is key for large mammals in these systems, subdividing land reduces the numbers of animals areas can support. To the extent that 300km2 of land in Laikipia will support 19% fewer cattle if subdivided into 10km2 parcels.
Large carnivores, which depend on wide-ranging herbivore prey, also need to range widely, and live at even lower densities than their prey. The Saharan cheetah, for example, occurs at one of the lowest densities ever documented for a big cat, with only one individual per 4,000km2.
The recent human migration crisis and growing insecurity in many dryland areas across the Sahara-Sahel has led to calls for large-scale border fencing in Africa, some of which stretch over several hundreds of kilometres.
There are also growing calls for large scale boundary fencing of protected areas as well as infrastructure developments, such as oil pipelines and railways, that cut across wildlife movement pathways. Kenya’s new Standard Gauge Railway line is a recent example.
On top of this is the problem of boundary fences erected around smaller plots of land. In southern Kenya fences put up around private farms have meshed together to form a large-scale barrier to wildlife movement.
In the face of these pressures, migratory, nomadic and wide ranging species depend on trans-boundary action for their long term survival.
The UN Convention on the Conservation of Migratory Species of Wild Animals , also known as the Bonn Convention, lays the legal foundation to safeguard species that need to move across international boundaries. It also provides for internationally coordinated conservation measures throughout their migratory range.
Africa is not alone in facing barrier threats. In central Asia, linear barriers also threaten this region’s migratory wildlife. For example, the border fence and railroad between Kazakhstan and Uzbekistan bisects the Saiga antelope migration between these countries. It has helped to put this population on the brink of extinction.
In response to barrier threats, the Convention on the Conservation of Migratory Species established the Central Asian Mammals Initiative This produced an important set of guidelines to inform fencing interventions and to help sustain migration corridors for migratory ungulates in Asia.
These guidelines are now being followed up with action. A project has been initiated to partially remove and modify the fences along the Trans-Mongolian Railway. This had formed a major barrier to movement for kulan (wild ass) and Mongolian gazelles. Furthermore, border fence modifications recommended by the Bonn Convention on the Conservation of Migratory Species are being implemented to enable Saiga to move, once again, between Kazakhstan and Uzbekistan.
African issues on the table
The Bonn Convention on the Conservation of Migratory Species has just held the Second Meeting of the Sessional Committee of its Scientific Council. This is in the run up to the Conference of the Parties in October where countries will come together to agree on new actions to save migratory species. Under discussion was a new African Carnivore Initiative, which seeks to develop a framework for the trans-boundary conservation of existing Bonn Convention listed large carnivore species, cheetah and African wild dog, and to add two as yet unlisted species, lion and leopard, to the initiative.
Also on the table was an important new initiative to maintain connectivity for terrestrial species, including an additional decision requested by the Zoological Society of London to address the problem of linear barriers in Africa, building on the experiences under the Central Asian Mammals Initiative.
If Africa to avoid catastrophic impacts of large scale fencing on its wildlife in the future, we must avoid repeating past mistakes. This will require further scientific research to better understand potential negative impacts of fencing and other linear barriers, and how best to mitigate such impacts, not just for wildlife, but also for ecosystem services and local communities.
At the Bonn Convention’s next Conference of Parties, nations will need to decide whether to implement important decisions to safeguard migratory species, including maintaining terrestrial connectivity. The fate of many wide ranging species hangs in the balance, and depends on governments supporting and, importantly, implementing, these decisions.