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Living planktonic foraminifera photos by Haruka Takagi, Katsunori Kimoto, Tetsuichi Fujiki, Hiroaki Saito, Christiane Schmidt4 , Michal Kucera and Kazuyoshi Moriya5, CC BY-SA 4.0 via Wikimedia Commons

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1) Orbulina universa, (2) Sphaeroidinella dehiscens, (3) Globigerinoides sacculifer, (4) Globigerinoides conglobatus, (5) Globigerinoides ruber (white), (6) Globigerinoides ruber (pink), (7) Globoturborotalita rubescens, (8) Globoturborotalita tenella, (9) Globigerinella calida, (10) Globigerinella siphonifera Type I, (11) Globigerinella siphonifera Type II, (12) Globigerinella adamsi, (13) Globigerina bulloides, (14) Turborotalita quinqueloba, (15) Turborotalita humilis, (16) Hastigerina pelagica, (17) Hastigerinella digitata, (18) Neogloboquadrina incompta, (19) Neogloboquadrina pachyderma, (20) Neogloboquadrina dutertrei, (21) Pulleniatina obliquiloculata, (22) Globorotalia inflata, (23) Globorotalia menardii, (24) Globorotalia scitula, (25) Globorotalia crassaformis, (26) Globorotalia truncatulinoides, (27) Candeina nitida, (28) Globigerinita glutinata, (29) Globigerinita uvula, and (30) Tenuitella fleisheri. Images by Haruka Takagi, Katsunori Kimoto, Tetsuichi Fujiki, Hiroaki Saito, Christiane Schmidt , Michal Kucera and Kazuyoshi Moriya CC BY-SA 4.0 via Wikimedia Commons

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This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Global temperature records are expected to exceed the 1.5 °C threshold for the first time this year. This has happened much sooner than predicted. So can life on the planet adapt quickly enough?

In our new research, published today in Nature, we explored the ability of tiny marine organisms called plankton to adapt to global warming. Our conclusion: some plankton are less able to adapt now than they were in the past.

Plankton live in the top few metres of ocean. These algae (phytoplankton) and animals (zooplankton) are transported by ocean currents as they do not actively swim.

Climate change is increasing the frequency of heatwaves in the sea. But predicting the future effects of climate change is difficult because some projections depend on ocean physics and chemistry, while others consider the effects on ecosystems and their services.

Some data suggest that current climate change have already altered the marine plankton dramatically. Models project a shift of plankton towards both poles (where ocean temperatures are cooler), and losses to zooplankton in the tropics but might not predict the patterns we see in data. Satellite data for plankton biomass are still too short term to determine trends through time.

To overcome these problems, we have compared how plankton responded to past environmental change and modelled how they could respond to future climate changes. As the scientist Charles Lyell said, “the past is the key to the present”.

We explored one of the best fossil records from a group of marine plankton with hard shells called Foraminifera. This comprehensive database of current and past distributions, compiled by researchers at the University of Bremen, has been collected by hundreds of scientists from the seafloor across the globe since the 1960s. We compared data from the last ice age, around 21,000 years ago, and modern records to see what happened when the world has previously warmed.

We used computational models, which combine climate trends with traits of marine plankton and their effect on marine plankton, to simulate the oceanic ecosystems from the last ice age to the pre-industrial age. Comparing the model with the data from the fossil record is giving us support that the model simulated the rules determining plankton growth and distribution.

We found that some subtropical and tropical species’ optimum temperature for peak growth and reproduction could deal with seawater warming in the past, supported by both fossil data and model. Colder water species of plankton managed to drift to flourish under more favourable water temperatures.

Our analysis shows that Foraminifera could handle the natural climate change, even without the need to adapt via evolution. But could they deal with the current warming and future changes in ocean conditions, such as temperature?

Future of the food chain

We used this model to predict the future under four different degrees of warming from 1.5 to 4 °C. Unfortunately, this type of plankton’s ability to deal with climate change is much more limited than it was during past warming. Our study highlights the difference between faster human-induced and slower-paced geological warming for marine plankton. Current climate change is too rapid and is reducing food supply due to ocean stratification, both making plankton difficult to adapt to this time.

Phytoplankton produce around 50% of the world’s oxygen. So every second breath we take comes from marine algae, while the rest comes from plants on land. Some plankton eat other plankton. That in turn gets eaten by fish and then marine mammals, so energy transfers further up the food chain. As it photosynthesises, phytoplankton is also a natural carbon fixation machine, storing 45 times more carbon than the atmosphere.

Around the world, many people depend heavily on food from the ocean as their primary protein sources. When climate change threatens marine plankton, this has huge knock-on effects throughout the rest of the marine food web. Plankton-eating marine mammals like whales won’t have enough food to prey on and there’ll be fewer fish to eat for predators (and people). Reducing warming magnitude and slowing down the warming rate are necessary to protect ocean health.

Timing of insurance retreat

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After a series of natural disasters – from the Canterbury earthquakes to Cyclone Gabrielle – real doubt hangs over the insurance options available to some New Zealand homeowners.

Increasingly, homes in certain areas are becoming uninsurable – or difficult to insure, at least. Insurers have decided the risk is too high to make covering it financially viable, leaving affected homeowners vulnerable.

The question of how insurers can continue to offer policies – all the while managing the growing risk from natural disasters – is becoming hard to ignore.

Insurers will have to explore alternative models and innovate if New Zealand is to adapt to future change.

Cautious insurers

There’s no general requirement in New Zealand that insurers cover anyone’s home, or that anyone’s home actually be insured.

Body-corporate groups are one exception. They must insure the units they manage. Mortgage lenders can also require borrowers to take out home insurance as part of their lending conditions.

When homeowners do get insurance, the risk of certain losses from natural disasters is automatically covered by the Natural Hazards Commission (previously known as the Earthquake Commission).

Even if a home insurance policy were to contain wording that, on the face of it, excluded this public natural-disaster cover, the law would treat the cover as included. At the same time, payouts are only managed by insurers, not financed by them.

The Canterbury earthquakes cost insurers NZ$21 billion and the Natural Hazards Commission $10 billion. And the risk of natural disasters more generally may be making insurers too cautious. They’re increasingly pulling out of areas they consider “high risk”.

That said, there are changes on the horizon. From mid-2025, insurers will have a general duty to “treat consumers fairly”. The Financial Markets Authority – the body responsible for enforcing financial-markets law – may potentially regard refusing home insurance to any consumer as a breach of the duty.

In other words, the Financial Markets Authority may end up forcing insurers to cover most of the country’s homes.

Billion-dollar payouts: liquefaction in the Christchurch suburb of Bexley after the 2011 earthquake. Getty Images

New insurance options

Future-proofing home insurance options will depend on the public and private sectors working together.

Many of the potential solutions are specific to how insurers take risk on. An insurer may decrease your premiums as an incentive for you to “disaster-proof” your home. If you don’t, the insurer may increase your premiums and limit its payouts to you, with individualised excesses or caps.

The insurer may even offer “parametric” insurance, which pays out less than traditional insurance, but faster.

For example, imagine a home insurance policy that covers any earthquake having its epicentre within 500 kilometres of your home, and measuring magnitude six or higher.

A traditional policy would pay out based on how much loss was caused (according to a loss adjuster). A parametric policy would simply pay out a small, pre‑agreed sum, based on the fact the earthquake occurred at all.

A parametric policy wouldn’t require you to prove any actual “loss” – beyond the inconvenience of having your home in the disaster zone.

While parametric insurance is relatively new worldwide, it’s an efficient solution for managing the risk of natural-disaster damage.

Reinsurance, co-insurance and ‘cat bonds’

An insurer may also transfer risk to one or more other insurance businesses – such as a “reinsurer”. If the insurer has to make a payout to you for a claim, the reinsurer then has to make a payout to the insurer for a portion of it.

The insurer may even “co‑insure” the risk. Co‑insurance is where two or more insurers cover different portions of the same risk. So, if you have your home co‑insured, you will have two or more insurers, each responsible for a portion of any claim.

Then there is the potential to transfer insured risk to entities that aren’t even insurance businesses. In some countries (such as Bermuda, the Cayman Islands and Ireland), the insurer can turn the risk into a “catastrophe bond” (also known as a “cat bond”).

Under a cat bond, the insurer arranges for expert investors to lend it capital in return for interest on the loans. The insurer eventually repays the capital, unless there is a specific natural disaster. In that case, the insurer keeps the capital, enabling it to pay out to the affected customers.

The insurer may even use the cat bond to create a “virtuous cycle”. More specifically, the insurer may reinvest the capital in “a project that reduces or prevents loss from the insured climate-related risk” (such as flooding).

Disaster-proofing the insurance industry

Key to improving the situation will be the public and private sectors working together to make climate-related disasters less frequent – and less serious when they occur.

The United Nations’ Intergovernmental Panel on Climate Change has advised on how the sectors could minimise climate-related risk. But they also have similar progress to make to minimise the risk of natural-disaster damage more generally, particularly from earthquakes.

It is important to build homes that are better disaster-proofed. And it is also important to address a major problem that many people don’t necessarily view as related to insurance – the cost of housing.

If New Zealanders wishing to own their homes didn’t have to invest as much of their money in housing as they do, the risk of damage to housing might be of less concern. Natural disaster wouldn’t have to mean financial disaster as much as it does today.

In the meantime, innovative insurance options will become more and more necessary.The Conversation

Christopher Whitehead, Lecturer in Law, Auckland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Carbon trading

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This 05 August webinar shares information about the Climate Change Commission’s first annual emissions reduction monitoring report, released in July 2024. The report provides an evidence-based, impartial view of whether the country is on course to reach its goals of reducing and removing greenhouse gas emissions. It provides insight into the progress made, challenges experienced, and opportunities and risks that need to be considered.

The following quote from Dr Rod Carr towards the end of the webinar, paints a realistic picture of what Aotearoa can expect in term of the economic our global standing and the risks. (Pages on this website explain Nationally Determined Contributions, the Paris Accord, and the Emissions Trading Scheme.)

Webinar question: What would happen if New Zealand wasn’t able or didn’t comply with our Nationally Determined Contributions (NDCs)? What are the implications for us?

Answers:

As time it goes on, meeting our NDCs is getting increasingly more difficult and expensive because of delay. 

Not meeting the NDCs: we would certainly expect to see greater scrutiny of our actions from our trading partners particularly where we have free trade agreements (FTAs) and particularly with those strong climate elements within them like the EU FTA. 

Not meeting them is also likely to come with a loss of influence and on the global scale in relation to climate change, which may mean we are in worse position to advocate for a response that takes into account our national circumstances. 

The final thing is that global consumers and customers are increasingly scrutinising their supply chains and looking for products that are reducing emissions, and so we do increase risks around loss of the global markets.

– Jo Hendy CE:  Video, The Climate Change Commission 2024 emissions reduction monitoring report, August 2024

When the rest of the world looks at New Zealand, if we haven’t met our national determine contributions—we won’t know on the 31st of December 2030 as it takes a couple of years for inventories and count up— but when the partners that we care about look at our behaviour and go, ‘Did you do all that you said you would? Did you do all that you said you would? And did you do all the things you could have done?’ That’s going to inform whether it’s ‘that you tried hard but missed’ or ‘you didn’t try’.

So foreign countries who are in incurring very real economic costs to reduce their emissions today— and that includes the Europeans, the Brits, and the Americans (there’s half a trillion U.S. dollars of taxpayers money being made available to reduce their emissions so the idea they’re not doing anything; that’s just wrong)—so when those countries look at NZ in the early 2030s and they look back to 2020, they go, ‘Well you could have made a better effort to, for example, decarbonized ground transport there were known technologies that were available, but you just chose to buy cheap high polluting cars. You could have chosen to stop burning as much coal and fossil gas to make electricity by investing more sooner in renewables, but you chose not to.’ I think that’s going to influence what the world thinks about New Zealand ‘s behaviour more than whether we did or did hit the exact number of tonnes for this decade.

And the rest of the world looks at New Zealand and says, ‘You didn’t try. You didn’t take up the known technologies. You are short sighted, selfish, and reckless in your use of the climate for profit.’ I think their attitudes to us will be very different than if we had tried hard and done all we could but things didn’t turn out well. 

– Dr Rod Carr, Video, The Climate Change Commission 2024 emissions reduction monitoring report, August 2024

New Zealand is one of the worst countries in the world in terms of meeting its commitments to keep temperatures under 1.5C. (Image: Climate Action Tracker)
New Zealand is one of the worst countries in the world in terms of meeting its commitments to keep temperatures under 1.5C. (Image: Climate Action Tracker)
New Zealand is also subsidising high greenhouse gas emissions industries by giving the agricultural sector a 100% discount (Image: Nature journal)
New Zealand is also subsidising high greenhouse gas emissions industries by giving the agricultural sector a 100% discount (Image: Nature journal)
Humidity forecasts over North America and the northeast Pacific Ocean. Kochov et al. / Nature

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Image: Humidity forecasts over North America and the northeast Pacific Ocean.
Kochov et al. / Nature Sanaa Hobeichi, UNSW Sydney




A new system for forecasting weather and predicting future climate uses artificial intelligence (AI) to achieve results comparable with the best existing models while using much less computer power, according to its creators.

In a paper published in Nature today, a team of researchers from Google, MIT, Harvard and the European Centre for Medium-Range Weather Forecasts say their model offers enormous “computational savings” and can “enhance the large-scale physical simulations that are essential for understanding and predicting the Earth system”.

The NeuralGCM model is the latest in a steady stream of research models that use advances in machine learning to make weather and climate predictions faster and cheaper.

What is NeuralGCM?

The NeuralGCM model aims to combine the best features of traditional models with a machine-learning approach.

At its core, NeuralGCM is what is called a “general circulation model”. It contains a mathematical description of the physical state of Earth’s atmosphere, and it solves complicated equations to predict what will happen in the future.

However, NeuralGCM also uses machine learning – a process of searching out patterns and regularities in vast troves of data – for some less well-understood physical processes, such as cloud formation. The hybrid approach makes sure that the output of the machine learning modules will be consistent with the laws of physics.

Google researchers explain the NeuralGCM model.

The resulting model can then be used for making forecasts of weather days and weeks in advance, as well as looking months and years ahead for climate predictions.

The researchers compared NeuralGCM against other models using a standardised set of forecasting tests called WeatherBench 2. For three- and five-day forecasts, NeuralGCM did about as well as other machine-learning weather models such as Pangu and GraphCast. For longer-range forecasts, over ten and 15 days, NeuralGCM was about as accurate as the best existing traditional models.

NeuralGCM was also quite successful in forecasting less-common weather phenomena, such as tropical cyclones and atmospheric rivers.

Why machine learning?

Machine learning models are based on algorithms that learn patterns in the data they are fed with, then use this learning to make predictions. Because climate and weather systems are highly complex, machine learning models require vast amounts of historical observations and satellite data for training.

The training process is very expensive and requires a lot of computer power. However, after a model is trained, using it to make predictions is fast and cheap. This is a large part of their appeal for weather forecasting.

The high cost of training and low cost of use is similar to other kinds of machine learning models. GPT-4, for example, reportedly took several months to train at a cost of more than US$100 million, but can respond to a query in moments.

A comparison of how NeuralGCM compares with leading models (AMIP) and real data (ERA5) at capturing climate change between 1980 and 2020. Google Research

A weakness of machine learning models is that they often struggle in unfamiliar situations – or in this case, extreme or unprecedented weather conditions. To do this, a model needs to be able to generalise, or extrapolate beyond the data it was trained on.

NeuralGCM appears to be better at this than other machine learning models, because its physics-based core provides some grounding in reality. As Earth’s climate changes, unprecedented weather conditions will become more common, and we don’t know how well machine learning models will keep up.

Nobody is actually using machine learning-based weather models for day-to-day forecasting yet. However, it is a very active area of research – and one way or another, we can be confident that the forecasts of the future will involve machine learning.The Conversation

Sanaa Hobeichi, Research Associate, Climate Change Research Centre, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

gold hydrogen

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Natural deposits are turning up all over the world – but how useful is it in our move away from fossil fuels?


This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Hydrogen will play a role in weaning us off fossil fuels. It can be used to power trains, planes and HGVs, as well as being a low-carbon alternative to coke in steelmaking and a way to warm our homes.

But where will we get it? The latest geological research suggests that cheap and plentiful supplies of naturally occurring hydrogen could be found right under our feet – although there’s a long way to go before we can say for sure how useful these stores of “gold” hydrogen will be.

The many ways to obtain hydrogen have an informal, colour-based naming scheme. At present, most of our supplies are “grey” hydrogen, which is made from natural gas. Grey hydrogen does nothing to reduce the climate impact of fossil fuels, because carbon dioxide is produced as a waste product and dumped into the atmosphere.

However, when this waste is captured and buried, what’s then known as “blue” hydrogen is a big improvement. It will allow rapid and relatively climate-friendly growth in hydrogen production in the short term.

In the future, we’ll use excess electricity from solar and wind farms to perform electrolysis – the electrical breaking up of water into the hydrogen and oxygen it’s made from. This “green” hydrogen is currently more expensive than blue hydrogen and is not yet widely exploited. But that is changing rapidly as governments around the world find ways to encourage it. There’s also “pink” hydrogen, made using nuclear energy.

Now a new hydrogen hue has appeared: gold (also sometimes known as white). Gold hydrogen is naturally occurring gas trapped in pockets under the ground – in much the same way as oil and natural gas. The question is: will any of these deposits (which are being found all over the world) be large enough to justify the cost of the drills, pipelines and so on that are needed to extract them?

Nature’s hydrogen

Geologists have long known that hydrogen is produced underground by the chemical reaction of iron-rich rocks with water, or when water breaks up by exposure to radioactive minerals.

But, because hydrogen molecules are small and light, they easily percolate through rock and escape into the atmosphere. Hydrogen also serves as a food source for many microorganisms. Consequently, natural underground deposits of the gas were assumed to be small and rare – and so, with the exception of some work done decades ago in the Soviet bloc, few attempts have been made to look for it. And if you don’t look, you don’t find.

Now, however, geologists are starting to look and large amounts of natural hydrogen are turning up all over the place. In October 2023, researchers at the French National Centre of Scientific Research discovered a particularly large reservoir of natural hydrogen in north-eastern France’s Lorraine coal basin. The reservoir may contain 250 million tonnes of naturally occurring hydrogen – enough to provide almost as much energy as the UK’s largest oil field (the Claire field, west of Shetland).

Smaller hydrogen reservoirs have been found in Spain and across Europe, as well as in Mali, Namibia, Brazil, the US and many other countries. So far there’s nothing in the UK, but geologists are starting to think about where to look.

Global distribution of suspected natural hydrogen deposits

A world map showing the distribution of natural hydrogen deposits.
Natural hydrogen deposits have been found in many parts of the world. David Waltham


Pros and cons

There’s much to learn before we’ll know if gold hydrogen could have a significant impact on the transition away from fossil fuels. Geologists need to understand better how and where hydrogen gas forms, how it migrates to the places it becomes trapped, and how long it stays there before leaking out or being consumed by microorganisms.

But there are clear benefits to exploiting this low-cost, low-impact energy source. The science and technology needed is similar to that already used by oil and gas firms so jobs, resources and knowledge could be redeployed.

That would help launch the “hydrogen economy” we need as part of a strategy to halt anthropogenic climate change. This will be true even if the deposits turn out to be very limited and, hence, merely a stopgap while we develop enough renewable electricity capacity to make green hydrogen viable.

There are downsides too. Exploiting natural hydrogen deposits could be used as an excuse to foot-drag on the need to cut greenhouse gas emissions immediately. We’ve seen this already with carbon capture and storage. Will gold hydrogen suffer the same fate of being unfairly pilloried because of over-hype by actors with a hidden agenda (namely some politicians and lobbyists)?

Another problem is that hydrogen exploration may accidentally lead to new discoveries of fossil fuel. For example, many of the known deposits of gold hydrogen also contain methane, which may need to be separated from the hydrogen and then reburied.

It’s also very hard to tell whether a possible subsurface “trap” contains oil, natural gas, hydrogen or just salt water. The ultimate test is to drill and see what’s there. But if a possible hydrogen field turns out to contain crude oil, how do we ensure it’s left in the ground?

The big question, though, is how seriously to take gold hydrogen. Will it turn out to be an over-hyped distraction of very limited utility? Or will it provide a pain-free path into a low-carbon future? The truth probably lies between these extremes, but only time (and further research) will tell us.

co2 drawdown

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Authors:

Volker Sick, Professor of Advanced Energy Research, Director of the Global CO2 Initiative, University of Michigan

Fred Mason, Gerry Stokes, Susan Fancy and Stephen McCord of the Global CO₂ Initiative contributed to this article.The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Producing concrete blocks with captured carbon has both economic and climate benefits.



Capturing carbon dioxide from the air or industries and recycling it can sound like a win-win climate solution. The greenhouse gas stays out of the atmosphere where it can warm the planet, and it avoids the use of more fossil fuels.

But not all carbon-capture projects offer the same economic and environmental benefits. In fact, some can actually worsen climate change.

I lead the Global CO₂ Initiative at the University of Michigan, where my colleagues and I study how to put captured carbon dioxide (CO₂) to use in ways that help protect the climate. To help figure out which projects will pay off and make these choices easier, we mapped out the pros and cons of the most common carbon sources and uses.


Replacing fossil fuels with captured carbon

Carbon plays a crucial role in many parts of our lives. Materials such as fertilizer, aviation fuel, textiles, detergents and much more depend on it. But years of research and the climate changes the world is already experiencing have made abundantly clear that humanity needs to urgently end the use of fossil fuels and remove the excess CO₂ from the atmosphere and oceans that have resulted from their use.

An illustration of a landscape shows how greenhouse gases and released, captured and stored in various ways, including oceans, land, forests and human activtiies.
Balancing the environmental carbon budget is complex, and active carbon management is necessary to stabilize the climate. University of Michigan, CC BY-ND


Some carbon materials can be replaced with carbon-free alternatives, such as using renewable energy to produce electricity. However, for other uses, such as aviation fuel or plastics, carbon will be harder to replace. For these, technologies are being developed to capture and recycle carbon.

Capturing excess CO₂ – from the oceans, atmosphere or industry – and using it for new purposes is called carbon capture, utilization and sequestration, or CCUS. Of all the options to handle captured CO₂, my colleagues and I favor using it to make products, but let’s examine all of them.


CCUS best and worst cases

With each method, the combination of the source of the CO₂ and its end use, or disposition, determines its environmental and economic consequences.

In the best cases, the process will leave less CO₂ in the environment than before. A strong example of this is using captured CO₂ to produce construction materials, such as concrete. It seals away the captured carbon and creates a product that has economic value.

A few methods are carbon-neutral, meaning they add no new CO₂ to the environment. For example, when using CO₂ captured from the air or oceans and turning it into fuel or food, the carbon returns to the atmosphere, but the use of captured carbon avoids the need for new carbon from fossil fuels.

Other combinations, however, are harmful because they increase the amount of excess CO₂ in the environment. One of the most common underground storage methods – enhanced oil recovery – is a prime example.

Underground carbon storage pros and cons

Projects for years have been capturing excess CO₂ and storing it underground in natural structures of porous rock, such as deep saline reservoirs, basalt or depleted oil or gas wells. This is called carbon capture and sequestration (CCS). If done right, geologic storage can durably remove large amounts of CO₂ from the atmosphere.

When the CO₂ is captured from air, water or biomass, this creates a carbon-negative process – less carbon is in the air afterward. However, if the CO₂ instead comes from new fossil fuel emissions, such as from a coal- or gas-fired power plant, carbon neutrality isn’t possible. No carbon-capture technology works at 100% efficiency, and some CO₂ will always escape into the air.

Capturing CO₂ is also expensive. If there is no product to sell, underground storage can become a costly service ultimately covered by taxes or fees, similar to paying for trash disposal.



One way to lower the cost is to sell the captured CO₂ for enhanced oil recovery – a common practice that pumps captured CO₂ into oil fields to push more oil out of the ground. While most of the CO₂ is expected to stay underground, the result is more fossil fuels that will eventually send more carbon dioxide into the atmosphere, eliminating the environmental benefit.

Using captured carbon for food and fuel

Short-lived materials made from CO₂ include aviation fuels, food, drugs and working fluids used in machining metals. These items aren’t particularly durable and will soon decompose, releasing CO₂ again. But the sale of the products yields economic value, helping pay for the process.

This CO₂ can be captured from the air again and used to make a future generation of products, which would create a sustainable, essentially circular carbon economy. However, this only works if the CO₂ is captured from the air or oceans. If the CO₂ comes from fossil fuel sources instead, this is new CO₂ that will be added to the environment when the products decompose. So even if it is captured again, it will worsen climate change.

Storing carbon in materials, such as concrete

Some minerals and waste materials can convert CO₂ to limestone or other rock materials. The long-lived materials created this way can be very durable, with lifetimes of longer than 100 years

A good example is concrete. CO₂ can react with particles in concrete, causing it to mineralize into solid form. The result is a useful product that can be sold instead of being stored underground. Other durable products include aggregates used in road construction, carbon fiber used in automotive, aerospace and defense ]applications and some polymers.

Volker Sick, director of the Global CO₂ Initiative at the University of Michigan and author of this article, discusses why carbon capture and its use has been slow to gain attention.

These materials provide the best combination of environmental impact and economic benefit when they are made with CO₂ captured from the atmosphere rather than new fossil fuel emissions.


Choose your carbon projects wisely

CCUS can be a useful solution, and governments have started pouring billions of dollars into its development. It must be closely monitored to ensure that carbon-capture technologies will not delay fossil fuel phaseout. It is an all-hands-on-deck effort to take the best combinations of CO₂ sources and disposition to achieve rapid scaling at an affordable cost to society.

Because climate change is such a complex problem that is harming people throughout the world, as well as future generations, I believe it is imperative that actions are not only fast, but also well thought out and based in evidence.

Authors:

Fred Mason, Gerry Stokes, Susan Fancy and Stephen McCord of the Global CO₂ Initiative contributed to this article.The Conversation

Volker Sick, Professor of Advanced Energy Research, Director of the Global CO2 Initiative, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

blue carbon

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Authors: Kerrylee Rogers, Associate Professor, University of Wollongong; Jeffrey Kelleway, Postdoctoral Research Fellow in Environmental Sciences, Macquarie University, and Neil Saintilan, Head, Department of Environmental Science, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Coastal wetlands don’t cover much global area but they punch well above their carbon weight by sequestering the most atmospheric carbon dioxide of all natural ecosystems.

Termed “blue carbon ecosystems” by virtue of their connection to the sea, the salty, oxygen-depleted soils in which wetlands grow are ideal for burying and storing organic carbon.

In our research, published in Nature, we found that carbon storage by coastal wetlands is linked to sea-level rise. Our findings suggest as sea levels rise, these wetlands can help mitigate climate change.

Sea-level rise benefits coastal wetlands

We looked at how changing sea levels over the past few millennia has affected coastal wetlands (mostly mangroves and saltmarshes). We found they adapt to rising sea levels by increasing the height of their soil layers, capturing mineral sediment and accumulating dense root material. Much of this is carbon-rich material, which means rising sea levels prompt the wetlands to store even more carbon.

We investigated how saltmarshes have responded to variations in “relative sea level” over the past few millennia. (Relative sea level is the position of the water’s edge in relation to the land rather than the total volume of water within the ocean, which is called the eustatic sea level.)

What does past sea-level rise tell us?

Global variation in the rate of sea-level rise over the past 6,000 years is largely related to the proximity of coastlines to ice sheets that extended over high northern latitudes during the last glacial period, some 26,000 years ago.

As ice sheets melted, northern continents slowly adjusted elevation in relation to the ocean due to flexure of the Earth’s mantle.

Karaaf Wetlands in Victoria, Australia. Boobook48/flickr, CC BY-NC-SA

For much of North America and Europe, this has resulted in a gradual rise in relative sea level over the past few thousand years. By contrast, the southern continents of Australia, South America and Africa were less affected by glacial ice sheets, and sea-level history on these coastlines more closely reflects ocean surface “eustatic” trends, which stabilised over this period.

Our analysis of carbon stored in more than 300 saltmarshes across six continents showed that coastlines subject to consistent relative sea-level rise over the past 6,000 years had, on average, two to four times more carbon in the upper 20cm of sediment, and five to nine times more carbon in the lower 50-100cm of sediment, compared with saltmarshes on coastlines where sea level was more stable over the same period.

In other words, on coastlines where sea level is rising, organic carbon is more efficiently buried as the wetland grows and carbon is stored safely below the surface.

Give wetlands more space

We propose that the difference in saltmarsh carbon storage in wetlands of the southern hemisphere and the North Atlantic is related to “accommodation space”: the space available for a wetland to store mineral and organic sediments.

Coastal wetlands live within the upper portion of the intertidal zone, roughly between mean sea level and the upper limit of high tide.

These tidal boundaries define where coastal wetlands can store mineral and organic material. As mineral and organic material accumulates within this zone it creates layers, raising the ground of the wetlands.

The coastal wetlands of Broome, Western Australia. Shutterstock

New accommodation space for storage of carbon is therefore created when the sea is rising, as has happened on many shorelines of the North Atlantic Ocean over the past 6,000 years.

To confirm this theory we analysed changes in carbon storage within a unique wetland that has experienced rapid relative sea-level rise over the past 30 years.

When underground mine supports were removed from a coal mine under Lake Macquarie in southeastern Australia in the 1980s, the shoreline subsided a metre in a matter of months, causing a relative rise in sea level.

Following this the rate of mineral accumulation doubled, and the rate of organic accumulation increased fourfold, with much of the organic material being carbon. The result suggests that sea-level rise over the coming decades might transform our relatively low-carbon southern hemisphere marshes into carbon sequestration hot-spots.

How to help coastal wetlands

The coastlines of Africa, Australia, China and South America, where stable sea levels over the past few millennia have constrained accommodation space, contain about half of the world’s saltmarshes.

Saltmarsh on the shores of Westernport Bay in Victoria. Author provided

A doubling of carbon sequestration in these wetlands, we’ve estimated, could remove an extra 5 million tonnes of CO₂ from the atmosphere per year. However, this potential benefit is compromised by the ongoing clearance and reclamation of these wetlands.

Preserving coastal wetlands is critical. Some coastal areas around the world have been cut off from tides to lessen floods, but restoring this connection will promote coastal wetlands – which also reduce the effects of floods – and carbon capture, as well as increase biodiversity and fisheries production.

In some cases, planning for future wetland expansion will mean restricting coastal developments, however these decisions will provide returns in terms of avoided nuisance flooding as the sea rises.

Finally, the increased carbon storage will help mitigate climate change. Wetlands store flood water, buffer the coast from storms, cycle nutrients through the ecosystem and provided vital sea and land habitat. They are precious, and worth protecting.

The authors would like to acknowledge the contribution of their colleagues, Janine Adams, Lisa Schile-Beers and Colin Woodroffe.

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We can’t just sit around and wait to see what will happen next. We need positive action.

I’ve read a lot of Climate Adaptation Plans and Strategies over the past the last few years, but He Toka Tū Moana Mō Maketū (Maketū Climate Change Adaptation Plan) is hand-down the best. It’s clearly laid out, outlines the community’s priorities, and can readily serve as a template to help every community around Aoteara develop their own Climate Adaptation Plans. Most important of all:

It’s iwi led, community driven, it’s a plan that’s been decided by those who live here. –  Elva Conroy, Kaitohotohu / Facilitator (Video; to listen Watch on Youtube)

Winner of the 2023 Supreme Planning Awards, the Maketū Climate Change Adaptation Plan was developed by Ngāti Pikiao Environmental Society, Te Rūnanga o Ngāti Whakaue ki Maketū , Whakaue Marae Trustees, and Conroy and Donald Consultants.

In the words of the Maketu Iwi Collective, ‘we will be resilient like the anchor stone Takaparore – strong and steadfast against the elements and tides of change and uncertainty. Regardless of what happens as a result of a changing environment, we will remain standing’. – New Zealand Planning Institute, April 2023.

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