Methane matters

Long-lived and short-lived greenhouse gases have been the subject of debate in New Zealand for some time. Understanding how they contribute to climate change is particularly important now the Government is considering a new emissions target for 2050. There are three options on the table:

  1. Net zero carbon dioxide
  2. Net zero long-lived gases and stabilised short-lived gases
  3. Net zero emissions across all greenhouse gases

This would replace the current target to cut emissions to 50% below 1990 levels by 2050.1

Which target?

The first target should be dismissed because it ignores other long-lived gases, including nitrous oxide, which accounts for over 10% of New Zealand’s emissions. Nitrous oxide lasts for over 120 years in the atmosphere. It has a warming effect that is more than 250 times that of carbon dioxide over a 100-year timespan.2

New Zealand’s nitrous oxide emissions have also been rising steadily since the 1990s as farming has expanded and intensified. These emissions stem from livestock urine and dung, and fertilisers. Cutting nitrous oxide emissions has the co-benefit of improving the health of our waterways, which have become heavily polluted by nitrate runoff from farms.3

This leaves us with the second and third targets, which is where it gets complicated. Should we cut all greenhouse gases to net zero? What is a long-lived and short-lived gas? And what does ‘net zero’ mean anyway?

Long versus short-lived greenhouse gases

Long-lived gases, including carbon dioxide and nitrous oxide, accumulate in the atmosphere. The total stock of historic emissions has locked in a degree of global warming that cannot be reversed. Ongoing long-lived emissions will continue to warm the climate.

Average global temperatures are now more than 1°C above pre-industrial levels.4 The only way to avoid the 2°C increase in global temperatures that we committed to under the 2015 Paris Agreement is to cut long-lived emissions to net zero. Both the second and third proposed targets take this into account.

Net zero implies that persistent long-lived emissions are offset, either by planting forests that absorb carbon dioxide or purchasing overseas ‘emissions credits’. The latter could, for example, serve to discourage deforestation abroad rather than planting more trees in New Zealand.

Short-lived gases also contribute to global warming, but the flow of emissions rather than the total stock in the atmosphere is what counts. This is because short-lived gases break down and exit the atmosphere faster. For example, methane is a short-lived greenhouse gas with an average atmospheric lifespan of just over 12 years.2 In New Zealand, methane from cattle and sheep makeup over 40% of our total emissions.3 Outside of New Zealand, methane is primarily emitted during oil and gas production, as well as equipment and pipeline leaks.

If atmospheric inflows of methane are equal to outflows then its contribution to global warming is fixed and, unlike long-lived gases, this does not worsen over time. Of course, this still implies some ‘warming’, even if it is not rising. This is the approach proposed for the second target.

Stabilising methane

It could seem fair to say that the New Zealand agricultural sector, which is responsible for the majority of methane emissions, should be allowed to continue emitting as long as it’s not making global warming any worse. However, implementing the second target is still likely to involve reducing methane emissions to shrink their overall contribution to climate change. This begs the question: how much methane-induced warming should be allowed? Or, at what level should we stabilise short-lived emissions?

The answer depends on our emissions budget ⎼ the amount that we can still emit in New Zealand, and globally, before breaching the 2°C temperature threshold agreed in Paris. The more long-lived gases we emit, the more we eat into our short-lived gases allowance. This is illustrated by the Productivity Commission’s diagram below:3

prod-comm-emissions-budget-long-v-short-lived-gases-e1530571389378.png

The second target leaves room for different interpretations of the appropriate stabilisation level. Once it is set up, the new Climate Change Commission will be able to advise on this. Depending on final wording of the second target, successive governments might be able to adjust the level. This could give us some flexibility in achieving our 2050 target, but would also result in some uncertainty for households and businesses. Since the chosen target is likely to remain in law until 2050 we ought to minimise ambiguity.

Warming decelerator

Deploying methane as a global warming ‘decelerator’ is the approach proposed for the third target. If outflows of short-lived gases exceed their flow into the atmosphere, this can actually counteract some of the warming being driven by historic long-lived emissions. If we cut methane emissions to net zero, their contribution to global warming will also reach zero within a few decades. The same cannot be said of long-lived carbon dioxide or nitrous oxide emissions.

The Paris Agreement requires us to “pursu(e) efforts to limit the temperature increase to 1.5°C”. This is a more aspirational target than 2°C, but the Agreement recognises this as the safer limit that “would significantly reduce the risks and impacts of climate change.”5  To have a high likelihood of limiting warming to 1.5°C, we need to limit the atmospheric concentration of greenhouse gases to 350 parts per million.6 But we exceeded this limit in 1988.7 The probability that warming is limited to just 1.5°C has been in steady decline ever since.

As the world continues to emit long-lived gases, cutting methane emissions can delay the arrival of the 1.5°C temperature limit. According to a leaked special report from the UN Intergovernmental Panel on Climate Change, this is expected to happen in 2040.8 Net zero methane would also dramatically improve our chances of avoiding warming of 2°C. Just as importantly, it might see us avoid climate tipping points, like the collapse of the Gulf Stream or the melting of the Arctic permafrost ⎼ events that cannot be reversed.

Methane has a warming effect over 80 times stronger than carbon dioxide over a 20-year period.2 This effect does not last forever, but the next few decades are crucial because we have already run up a debt. Cutting methane emissions to net zero is like selling your car to meet your mortgage repayments and avoid foreclosure.

Our climate, your say

It is difficult to conclude whether the second or third target is best. Both are grounded in science and make sense. 

Should New Zealand cattle, sheep and dairy farmers cut exports and innovate their way to net zero? Industry, as well as the energy and waste sectors that produce long-lived emissions, certainly must. 

New Zealand will not remain unaffected by sea level rises, extreme weather events, drought and wildfires, or an increase in airborne diseases and the other effects of climate change. Yet, we know that developing countries will bear the brunt of this. Should New Zealand cut all emissions to net zero by 2050, so our neighbours in the low-lying coral atolls in the Pacific have the best chance of preserving their homes?

The choice is ultimately a moral one, even cosmopolitan, as it asks us to consider the benefits to people beyond our borders.

You can make a submission here: Our Climate. Your Say.


Footnotes:
[1] New Zealand 2050 target, Ministry for the Environment
[2] Global Warming PotentialIPCC Working Group 1, Assessment Report 5, Chapter 8, Table 8.7
[3] Low-emissions economyProductivity Commission
[4] Climate Monitoring, US National Oceanic and Atmospheric Administration
[5] The Paris Agreement, UNFCCC
[6] Radiative Forcing Stabilisation Level, IPCC Working Group 2, Assessment Report 4, Chapter 19, Figure 19.1
[7] Atmospheric carbon dioxide, US National Oceanic and Atmospheric Administration
[8] IPCC Final Draft ReportReuters


Further reading:

New Zealand Agricultural Greenhouse Gas Research Centre

NZ Climate Change Research Institute, Victoria University

Ministry for the Environment

 

Net Zero

New Zealand must map out a path to carbon neutrality by 2050 as our challenges are harbingers for the rest of the world. We already have a 85% renewable power mix, but we must figure out how to close this gap. Transport is responsible for most of New Zealand’s carbon dioxide emissions and 20% of total emissions, as is the case globally. Agricultural emissions make up more than half of our emissions profile. Dairy, meat, crops and horticultural products are exported, so international dietary preferences must figure in our national debate on climate change. We must also ask ourselves if aluminium production still has a place in New Zealand, and how many trees we should plant each year.

I moved home to New Zealand late in 2017, just a few weeks after a new centre-left government was formed. The Labour Party entered into a coalition with New Zealand First and a confidence-and-supply agreement with the Greens. Before Christmas, the new climate change minister and Greens’ party leader announced the Government’s intention to pass a Zero Carbon Act, whereby the New Zealand economy would achieve carbon neutrality by 2050. Industry, think-tanks and public sector officials have produced huge volumes of data, modelling, analyses and arguments since then. Within the last few weeks, the Interim Climate Change Commission was announced and the Productivity Commission published a 500-page draft report on the transition to a low-emissions economy. We all want to know what do we need to do to reach net zero.

I am reviving this blog with the aim of discussing climate change issues in New Zealand as I believe what we do here matters greatly. Small-emitting nations are responsible for up to 30% of total global greenhouse gas emissions. Given the nature of our challenges, decarbonising power, transport, agriculture and industry in New Zealand can provide a blueprint for decarbonising the world. We have the opportunity to demonstrate how to reach net zero.

100% renewables

Around 85% of New Zealand’s annual electricity supply is generated from renewable sources. Gas or coal-fired generation is used to meet winter demand peaks and back up supply in low rainfall years.  Hydroelectricity constitutes more than half of the national power mix. In a high hydrology scenario, with good seasonal rainfall and snow melt, hydro-power can meet up to 65% of our annual power needs, but dry years present a great challenge and a barrier to reaching 100% renewables.1

Norway is often held up as an example, given its comparable population size and reliance on hydro-power. However, the tiny Nordic nation has almost six times the amount of lake storage available in New Zealand. That’s just geography and topography. We can’t build another lake. Or we could, but the major legacy hydro-power schemes in New Zealand already disturb our ecosystems and divert major waterways so as to generate power. Under current resource management laws, it is highly unlikely that a new large-scale hydro-power scheme would get built in New Zealand. We could feasibly expand lake storage in current schemes, but not double it, which is what would be required. Further, this would do little to address the main barrier to reaching a 100% renewable power supply, which is our dry-year risk.

Wind power

At an emissions price of $75 or greater it will be economic to build enough wind farms to reach about 95% renewables in New Zealand, according to Concept Consulting. Wind farms will be important to ousting baseload gas and coal power plants over the next decade. This means that fossil fuels will never need be burnt to meet electricity demand when wind is available. Wind power only comprises around 6% of current supply, so resource consent and project permitting should be fast-tracked to encourage new build. Today, a significant number of wind projects have actually been consented, over 2.5GW according to the NZ Wind Energy Association, but project developers are waiting for prices to rise before starting construction. However, wind power cannot ensure our power supply is 100% renewable in a dry year since it is not guaranteed to be available during winter peaks when demand is at its highest. Grid-scale or rooftop solar exacerbates the seasonal storage challenge as it only generates during periods of low demand and has a much higher output during the summer. We need power sources that are as flexible as coal and gas-fired power plants to meet seasonal demand.

Another important issue is that wind is highly correlated throughout New Zealand. To simplify, if it is a windy day in Auckland it is likely to be a windy day in Wellington. When south-westerlies or westerlies, or any given weather system, move across New Zealand we get high volumes of generation at all or most wind farms, but when the weather is mild then wind generation is generally low throughout the country. More geographically diverse locations can be selected for future wind farms to reduce the effect of this correlation. Nevertheless, New Zealand is an island nation lacking any electricity interconnectors to other countries, so we cannot import electricity from a neighbour as happens in the European Union or the United States when wind power cuts out. We are on our own.

Big batteries

Grid-scale battery storage projects have been making headlines around the world. Tesla installed a massive battery in South Australia after Elon Musk made a promise to do it in 100 days or for free on Twitter. Bloomberg New Energy Finance’s (BNEF) lithium-ion battery price index shows a fall from US$1,000 per kWh in 2010 to US$209 per kWh in 2017. This fantastic cost decline is a cause for celebration. It will bring more storage into our homes and bring more flexible services to our power grids. It has already brought us mass-market electric vehicles. Nevertheless, this technology cannot economically provide seasonal or dry-year power storage of the scale required at present. They just do not pack as much punch as hydro storage.

Let’s make some optimistic assumptions. Suppose, Tesla can manufacture a 10kW battery next year. The buffer that we might need in a dry year is 4000 GWh in New Zealand – this is the extra energy we can store in hydro lakes during wet years. We have around 1.5 million households. This suggests we need 400 million batteries, or over 250 Tesla Powerwalls per household. Even at a discounted price of just US$2000 this would require an investment of over US$500,000 per household or US$800 trillion in total. More than four times our current GDP. We could spend that money more wisely to reduce our greenhouse gas emissions.

Car culture

Power sector emissions have declined 13% since 1990 and make up less than 10% of total emissions. In the same period, transport emissions rose 70% and constitute 20% to New Zealand’s emissions. Car ownership reached its highest level ever last year, at 774 light vehicles for every 1,000 New Zealanders. This is almost the highest vehicle ownership per person worldwide (Ministry of Transport).

This is the beast we must tackle. Electrification is the key pathway with existing technology to cut the majority of transport emissions. To charge electric passenger vehicles and e-buses, electrify trains, and reduce fossil fuel usage for heating, a reliable and affordable electricity supply is crucial. Rising power prices or an uncertain supply could frustrate decarbonisation in these emissions-intensive sectors and lead to worse overall outcomes (Concept Consulting). That’s why it is vital to not prematurely force a 100% renewables goal in the power sector.

Nevertheless, with more wind, batteries and additional geothermal power plants, it is technically feasible to reach the 100% renewables target when we have average or high rainfall. This would be achieved at great expense and put significant upwards pressure on power prices. Other flexible technologies, such as demand response or renewable power-to-gas, hold great potential to help New Zealand reach 100% renewables. Biomass or tidal power generation could emerge as affordable means to generate electricity in New Zealand in the next few decades. Solar and wind offer a comparatively low-cost pathway to reduce emissions in most countries that currently have a high share of coal and gas-fired generation, but how we plug the gap between 95% and 100% in New Zealand isn’t obvious yet.

photo-1472718888560-1a1292f1cccb

Farming

The New Zealand Emissions Trading Scheme (ETS) is our main tool for encouraging decarbonisation. The scheme requires emitters to pay for each tonne of carbon dioxide or other greenhouse gas produced – this is called an emissions unit. Farmers are currently exempt from participating in the ETS, which covers energy, waste and industry. To achieve net zero this will have to change since agriculture contributes over half of our emissions. To ensure a gradual transition for farmers, they should receive free emissions units upfront and have trading at the full emissions price phased in over time.

Carbon dioxide is not the culprit in the agricultural sector. In New Zealand, the main agricultural greenhouse gases are nitrous oxide and methane.
Nitrous oxide is a potent, long-lived greenhouse gas with over 200 times the global warming potential of carbon dioxide. Produced from livestock urine and dung, NO2 emissions rose 48.5% between 1990 and 2015, and make up 10% of our total emissions.1

Methane is a short-lived gas in the atmosphere. In other countries it is mainly generated as a byproduct of oil and gas exploration. These are called ‘fugitive’ emissions. In New Zealand, methane is biological in origin stemming from cattle and sheep. It has a very powerful heating effect in the short-term and can serve to accelerate or delay peak temperature or tipping points in the climate system.

Changing land-use from dairy, sheep and cattle farming to new forests or low-emissions crops and horticulture (growing fruit, vegetables and flowers) is key to achieving carbon neutrality in New Zealand by 2050. This implies that fewer sheep and cattle will be farmed in the future. Reducing, though perhaps not eliminating, dairy and meat exports raises important questions about food production. The carbon footprint associated with a diet rich in animal protein is an issue that is likely to loom larger in public debate.

Planting trees

Planting forests, also known as afforestation, currently offsets about 30% of New Zealand’s greenhouse gas emissions annually.1 At the moment, foresters can voluntarily participate in the ETS and profit from offsetting emissions. However, the registration fees and complexities of trading discourage small foresters from joining the scheme. Facilitating forest-owners participation in the ETS will provide new sources of income to agricultural regions, as farmers switch from pastoral farming and dairying to horticulture, crops or forestry.

All pathways to net zero, require forestry to play a major role. Afforestation is like a credit card, buying us time to develop alternative technologies to replace current agricultural and industrial processes. A methane vaccine for animals or other biological inhibitors that can be mixed with their feed are being researched, but these technologies remain unproven. Selective breeding, though it can take decades, will also continue reduce the amount of methane produced per animal.

Beyond 2050, when all economically viable land for new forests has been used, emissions offsets or reductions will have to come from elsewhere, so research and development funding is important. Government funding for research into emissions mitigation technologies is about NZ$20m per year, with roughly NZ$16m going to agricultural programmes. Given the contribution of agriculture to GDP (6% in 2015), and its proportion of total emissions, this is a small sum. More than NZ$1.5 billion is spent funding innovation in other areas.1 One option is to use revenues from the auctioning of emissions units to fund new mitigation technologies and research.

There are few affordable means to cut emissions from pastoral and dairy farming without reducing herd populations at present. Forestry, cropping and horticulture will offer alternatives. If all sectors are covered by the Emissions Trading Scheme, businesses that reduce their emissions will be rewarded and pay for fewer emissions units. It is the main tool we have to encourage the changes and innovation required in all sectors to dramatically cut our emissions and reach net zero by 2050 in New Zealand.


Footnote:

[1] Statistics & figures sourced from the Productivity Commission’s draft report unless otherwise referenced, Low-emissions economy, 27 April 2018.

This article was reprinted with permission by The Spinoff on 28 March 2018 at: https://thespinoff.co.nz/science/28-05-2018/nz-has-pledged-zero-carbon-by-2050-how-on-earth-can-we-get-there/ 

Welcome

The perfect energy source – that is cheap, safe, abundant, reliable, environmentally friendly and producible on any scale – doesn’t exist.[i] When it comes to energy, we can’t avoid making judgment calls. Energy is policy. It is a choice.

Do we want the most stable, reliable electricity production possible? A government-sponsored nuclear industry, like France’s, makes sense.

Or is cheapest best? This is most relevant to developing economies. Coal is abundant, transportable and very cheap. And very polluting. China is the world’s biggest consumer of coal, but it still plays a huge role in countries like Germany, Poland and the US.

Or do we want to reverse climate change? If so, our society needs revolutionary rethinking. Cars, freight and planes would have to all but disappear.

Sunshine and wind are abundant in many countries and not polluting in themselves (the production of parts, installation and noise pollution aside). But who will bear cost of realising an entirely new smart electricity grid? What power generation will be used as back-up on the days the wind doesn’t blow and the sun doesn’t shine?

This blog is intentionally bipartisan. I am interested in solutions, not ideology. Developing solutions that address climate change and pollution, while also supporting development and fairness, and allowing for profitability. This requires both creative thinking and diverse inputs. We can benefit from the efficiency and dynamism markets encourage without rejecting the crucial role governments can and do play – and should, since safety is at stake.

Misunderstanding of energy issues is pervasive – exacerbated by misleading articles in the media. And our politicians struggle to promote their own energy policies, as they themselves lack clarity about the issues.

A lot of activists with worthy motivations – preventing dangerous climate change from engulfing the planet or radiation from poisoning another generation of young Japanese – make hasty suggestions about how to deal with the problems that worry them.

This isn’t surprising as energy issues are complex. They don’t conform to classic economic models. Each sector seems to have its own strange dynamic. Gas is regional. It is transported by pipelines and blighted by geopolitical manoeuvring. And it has yet to make strong in-roads into the transport fuel market to compete with petrol. It is still mainly being used by industry and for heating.

Oil is traded a hundred times more in paper than in physical barrels. This liquidity stems both from its being easy to transport as well as from strong competition. Yet, fundamental constraints affect the oil market too. The stuff of value is the refined petroleum product obtained from processing crudes. And the refineries that do this are both very expensive and inflexible, and can only be used to refine a particular crude oil.

Oil’s price level directly affects inflation and the cost of living in most of the countries that consume it. And, in the big producing countries, it often forms the backbone of their governments’ budgets, and can dramatically increase or decrease income levels.

Electricity may not be the biggest contributor to climate change, but the debate around renewable energy, particularly solar and wind power, takes centre-stage here. Electricity markets reflect their infrastructural base as electricity can’t be stored it must be consumed immediately after it is created.

The make-up of electricity systems varies greatly according to country – and within nations. For example, New Zealand’s predominantly renewable electricity mix is based on geothermal and hydropower. This is only possible because of the country’s local geographic and climatic conditions.

The often forgotten market is dirty, but abundant coal.

Coal is usually local. It is also the fuel that would suffer most if a price for carbon was integrated in its valuation. A little appreciated fact is that shifting 1% of global coal usage to natural gas would be the equivalent of increasing current renewable energy production by 11%.[ii]

A good understanding of the dynamics of the energy industry and markets is necessary if we are to be serious about addressing the global problems we face; whether these are fair consumer prices, climate change, energy poverty and access, economic and industrial growth, energy supply security or global financial stability. I’m very serious about these – although I don’t believe the solutions are easy or obvious. But we mustn’t be dismayed or dissuaded by the complexity of problems that face us. We will discuss them here.


[i] Although a cheekier analyst might suggest that energy efficiency – not wasting energy – is the cheapest fuel we have.

[ii] Data from BP Energy 2035 Energy Forecast, C.Ruhl, January 2014