New Zealand’s emissions reduction targets and proposed emissions budgets should be the floor of our ambition, not the ceiling, Marc Daalder argues
COMMENT: On Wednesday, the Climate Change Commission unveiled an updated set of proposed limits for how much greenhouse gases New Zealand should emit over the next 14 years.
While climate activists are right to note that these budgets are not the best we can do, they are still ambitious and meeting them is no foregone conclusion. It will require significant changes to the way we live our lives – in the commission’s words, “transformational and lasting change across society and the economy”.
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This includes driving less and walking, cycling and taking public transport more. It means we soon won’t be building new houses with fossil gas pipes or buying new cars that run on fossil fuels. It means having fewer sheep (gasp!) and fewer cows (the horror!) – the commission estimated we’re already likely to have 8 percent fewer dairy cattle in 2030 than today, with a corresponding 4 percent decrease in milk production, but that a bit of hard work could reduce livestock numbers by 13 percent instead, without any further productivity loss.
These are bold goals. The commission clearly has a vision of a what a low-carbon Aotearoa might look like. That’s something we can all agree on.
What we might tear each other to pieces over is the way to get there.
The commission’s proposed budgets – which would see average emissions in the second half of this decade fall by 20 percent from 2019 levels, and by 35 percent from the same levels in the first half of the 2030s – must not be the limits of our ambition.
Our various emissions reduction targets – an international Paris commitment, and Zero Carbon Act goals of reducing methane from agriculture and waste by 10 percent by 2030 and by 24 to 47 percent by 2050, and reducing all other emissions to net zero by 2050 – should likewise be seen not as ceilings, but floors.
These targets were set with the aim of getting New Zealand to do its part in the global effort to limit warming to 1.5 degrees above preindustrial levels. The budgets are designed to help us achieve those targets.
Unfortunately, that laudable aim of limiting warming to 1.5 degrees rests on a coin flip. New Zealand’s targets and budgets are built on pathways from the Intergovernmental Panel on Climate Change (IPCC) – the leading international expert body on what we need to do to fight the climate crisis. But those pathways are only considered “likely” to limit warming to 1.5 degrees with limited or no overshoot, with “likely” defined as a 50 to 66 percent chance.
Moreover, every single one of these scenarios relies on removing carbon dioxide from the atmosphere after 2050 – between 100 billion and one trillion tonnes of CO2 would be sucked up in the 21st century in the IPCC pathways. Some of this could be done with afforestation, but many scenarios also require new carbon capture and storage technology which is not yet proven at scale.
The greater the reliance on this unproven carbon capture technology, the greater the risk of overshooting 1.5 degrees. The fourth pathway in the above chart from the IPCC risks warming reaching nearly 1.7 degrees before being brought under control by the new technology.
But the consequences of surpassing 1.5 degrees are dire. There are concerns that reaching two degrees of warming could set off a self-reinforcing melt of the West Antarctic Ice Sheet – which contains enough water to raise sea levels by 3.3 metres. This is still hotly contested by scientists, but other impacts are less controversial: Coral could be entirely eliminated, the number of insects, plants and animals exposed to habitat loss would double as compared with 1.5 degrees, ice-free arctic summers would be 10 times more common and more than 90 percent of coastlines worldwide would be exposed to at least 20 centimetres of sea-level rise.
This isn’t the sort of thing you bet on a coin flip.
That’s why the Climate Commission’s budgets and the Zero Carbon Act targets must be seen as a floor, not a ceiling, for our ambition. As new budgets are devised, we must consistently commit to greater climate action – because new technology will become available, because existing emissions-reducing tech will become cheaper and more accessible and because the seriousness of the crisis will only become clearer.
Attitudes like that of Beef and Lamb, which complained that the commission saw an opportunity to reduce biogenic methane emissions by 12 percent by 2030, instead of the Zero Carbon Act target of 10 percent, must be discarded.
This is particularly true for the agriculture sector, which under the commission’s demonstrative pathway would not even fall within the interquartile range of IPCC’s 1.5 degree pathways.
In other words, more than 75 percent of the modelled IPCC pathways which limited warming to 1.5 degrees with limited or no overshoot require greater reductions in agricultural methane than the commission has asked the sector to make.
The other major greenhouse gas from the agriculture sector, nitrous oxide, is also given close to a free pass. The IPCC interquartile range calls for emissions of this gas from the primary sector to be somewhere between 3 percent above 2010 levels by 2030 or 21 percent below those levels by the same date. Under the commission’s path, agricultural nitrous oxide emissions would fall a measly 3 percent.
Worse, the IPCC pathways are devised for a world where the vast bulk of warming is due to carbon dioxide.
In New Zealand, however, agricultural methane and nitrous oxide made up 37.2 and 9.6 percent of the country's 2019 gross emissions, respectively.
That's when their warming impact is compared to that of carbon dioxide on a 100-year time scale. Methane is 28 times more potent by this measure and nitrous oxide is 265 times worse.
It's because of this that biogenic methane has been New Zealand's greatest contribution to global warming, after carbon dioxide released during preindustrial deforestation.
While CO2 in the atmosphere will continue to linger for centuries, contributing to warming over that entire time, it is the next couple of decades that are most crucial to averting 1.5 degrees of warming.
In the worst-case scenario, a Carbon Brief analysis found, the world could cross the 1.5 degree threshold in 2026 - just as New Zealand embarks on achieving its second emissions budget.
Rapidly reducing emissions of the gases that contribute most heavily to warming in the short-term could greatly aid our pursuit of the 1.5 degree goal.
This isn't idle speculation: the United Nations Environment Programme recently called for a 45 percent reduction in methane emissions by 2030, globally. This would include methane from fossil fuel production, not just livestock and waste, but would avert 0.3 degrees of warming by the 2040s.
A 10 or 12 percent reduction in biogenic methane may technically fall within the IPCC range, but we must not stop there.
Whenever an opportunity arises to reduce emissions further and faster, we must seize it - otherwise we risk leaving that all-important 1.5 degree target to a simple coin flip.