Are wetlands really a natural sink?
Wetlands are being promoted as a way to curb climate change but they might do the opposite, says
Nature-based solutions are being promoted as the way forward for the planet. There is little doubt that they sound good. We appear to have been programmed through advertising to regard anything labelled “natural” as beneficial, despite the fact that wildlife documentaries show that not all in nature is benign.
Survival of the fittest (most fit for the environment – including fastest to escape and fattest to survive the lean times) comes to mind.
However, the phrase “nature-based solutions” suggests that only the good will be chosen for implementation.
The solutions are being explained as a way to “leverage nature and the power of healthy ecosystems to protect people, optimise infrastructure and safeguard a stable and biodiverse future”.
The definition given by the International Union for Conservation of Nature (a membership Union composed of both government and civil society organisations) appears to have been modified by New Zealanders to include adaptation but the general intent is clear — work with nature to create a better future.
The Ministry for the Environment has distilled the essence: to tackle the climate emergency and to design our response to the climate crisis in a way that protects, enhances and restores nature where possible.
A major part of the climate response is to develop a carbon removal strategy.
Climate Change Minister James Shaw and Forestry Minister Peeni Henare released a Cabinet Environment, Energy and Climate Committee report in August.
The report was labelled “in confidence”, but the ministers released it proactively after inquiry. (They also said the redacted parts would not be “un-redacted” if a request was made under the Official Information Act.)
The ministers suggest that New Zealand needs a broader range of carbon dioxide sinks than forestry alone and proposed increasing durable storage of carbon dioxide in geological, terrestrial, or ocean reservoirs, or in products.
The latter include vegetation, sediment and organic soils that are stored through biological processes.
Chemical processes and reducing emissions from drained organic soils are also mentioned in the document.
The big questions are how changes can be achieved, whether they will be big enough to have any impact, how much they will cost and whether there will be any unintended consequences.
The UK was ahead of us in announcing nature-based solutions... and has now calculated that its commitments will cost double what was originally thought.
The report estimated that the costs of meeting environmental priorities through land management in the UK would be £4.4 billion per annum over 10 years.
The authors warned that the study did not try and estimate the costs associated with the administration of public or privately funded environmental land management schemes (meaning in real terms they underestimate the cost to the country).
The largest annual costs related to net zero land use change (£1.2 billion), followed by priority habitat creation, restoration, and maintenance (£1b).
The latter included woodlands, bogs and fens (marshes) — wetlands.
There used to be more wetlands globally than there are now.
But though restoration of wetlands is being promoted as a nature-based solution in the UK and in New Zealand, it should be remembered that wetlands release greenhouse gases into the atmosphere.
Methane release is well known (marsh gas, will-o-the-wisps, ignis fatuus), but they also release carbon dioxide and nitrous oxides.
The balance of growth and decomposition of organic matter is what determines whether wetlands are a sink or a source of greenhouse gases.
Research published in Nature Climate Change in March suggests that warming temperatures are weakening the ability of wetlands to act as a sink.
The authors reported that under a global temperature increase of 1.5C to 2C, the “100-year global warming potential of wetlands” could rise by 57 per cent.
Further, increased atmospheric methane from wetlands has already been recorded.
Notwithstanding that the concept of restoring wetlands seems “natural”, doing so might lead to unintended consequences.
The fact that natural methane from wetlands is not being targeted with a tax, in contrast to the natural methane from ruminants burping, comes down to global politics.
In further contrast, the suggestion NZ should reduce ruminant numbers at the very same time as new international airports are planned to boost tourist numbers, and delight is expressed in finding a new home for Supercars where drivers risk life and limb to get back to their starting point as fast as possible while burning fossil fuels, is lunacy.
Yet another bizarre contrast is the way comments are made about (COP) Conference of Party meetings (and then justifications made on the basis that if they work they will have major benefits), but the carbon impact of sporting events is not discussed.
Perhaps Sport Minister Grant Robertson should be part of the group creating the Carbon Removals Strategy. Tourism Minister Peeni Henare, is already there with his forestry hat.
A discussion document on New Zealand’s carbon removal strategy has been signalled for release to the public in early 2024. But maybe sense will prevail before then.
The suggestion NZ should reduce ruminant numbers at the very same time as new international airports are planned to boost tourist numbers, and delight is expressed in finding a new home for Supercars where drivers risk life and limb to get back to their starting point as fast as possible while burning fossil fuels, is lunacy.