New research: nitrous oxide emissions 300 times more powerful than CO₂ are jeopardising Earth’s future



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Pep Canadell, CSIRO; Eric Davidson, University of Maryland, Baltimore; Glen Peters, Center for International Climate and Environment Research – Oslo; Hanqin Tian, Auburn University; Michael Prather, University of California, Irvine; Paul Krummel, CSIRO; Rob Jackson, Stanford University; Rona Thompson, Norwegian Institute for Air Research, and Wilfried Winiwarter, International Institute for Applied Systems Analysis (IIASA)

Nitrous oxide from agriculture and other sources is accumulating in the atmosphere so quickly it puts Earth on track for a dangerous 3℃ warming this century, our new research has found.

Each year, more than 100 million tonnes of nitrogen are spread on crops in the form of synthetic fertiliser. The same amount again is put onto pastures and crops in manure from livestock.

This colossal amount of nitrogen makes crops and pastures grow more abundantly. But it also releases nitrous oxide (N₂O), a greenhouse gas.

Agriculture is the main cause of the increasing concentrations, and is likely to remain so this century. N₂O emissions from agriculture and industry can be reduced, and we must take urgent action if we hope to stabilise Earth’s climate.

2000 years of atmospheric nitrous oxide concentrations. Observations taken from ice cores and atmosphere. Source: BoM/CSIRO/AAD.

Where does nitrous oxide come from?

We found that N₂O emissions from natural sources, such as soils and oceans, have not changed much in recent decades. But emissions from human sources have increased rapidly.

Atmospheric concentrations of N₂O reached 331 parts per billion in 2018, 22% above levels around the year 1750, before the industrial era began.

Agriculture caused almost 70% of global N₂O emissions in the decade to 2016. The emissions are created through microbial processes in soils. The use of nitrogen in synthetic fertilisers and manure is a key driver of this process.

Other human sources of N₂O include the chemical industry, waste water and the burning of fossil fuels.




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N₂O is destroyed in the upper atmosphere, primarily by solar radiation. But humans are emitting N₂O faster than it’s being destroyed, so it’s accumulating in the atmosphere.

N₂O both depletes the ozone layer and contributes to global warming.

As a greenhouse gas, N₂O has 300 times the warming potential of carbon dioxide (CO₂) and stays in the atmosphere for an average 116 years. It’s the third most important greenhouse gas after CO₂ (which lasts up to thousands of years in the atmosphere) and methane.

N₂O depletes the ozone layer when it interacts with ozone gas in the stratosphere. Other ozone-depleting substances, such as chemicals containing chlorine and bromine, have been banned under the United Nations Montreal Protocol. N₂O is not banned under the protocol, although the Paris Agreement seeks to reduce its concentrations.

A farmer emptying fertiliser into machinery
Reducing fertiliser use on farms is critical to reducing N₂O emissions.
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What we found

The Intergovernmental Panel on Climate Change has developed scenarios for the future, outlining the different pathways the world could take on emission reduction by 2100. Our research found N₂O concentrations have begun to exceed the levels predicted across all scenarios.

The current concentrations are in line with a global average temperature increase of well above 3℃ this century.

We found that global human-caused N₂O emissions have grown by 30% over the past three decades. Emissions from agriculture mostly came from synthetic nitrogen fertiliser used in East Asia, Europe, South Asia and North America. Emissions from Africa and South America are dominated by emissions from livestock manure.

In terms of emissions growth, the highest contributions come from emerging economies – particularly Brazil, China, and India – where crop production and livestock numbers have increased rapidly in recent decades.

N₂O emissions from Australia have been stable over the past decade. Increase in emissions from agriculture and waste have been offset by a decline in emissions from industry and fossil fuels.

Regional changes in N₂O emissions from human activities, from 1980 to 2016, in million tons of nitrogen per year. Data from: Tian et al. 2020, Nature. Source: Global Carbon Project & International Nitrogen Initiative.

What to do?

N₂O must be part of efforts to reduce greenhouse gas emissions, and there is already work being done. Since the late 1990s, for example, efforts to reduce emissions from the chemicals industry have been successful, particularly in the production of nylon, in the United States, Europe and Japan.

Reducing emissions from agriculture is more difficult – food production must be maintained and there is no simple alternative to nitrogen fertilisers. But some options do exist.




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In Europe over the past two decades, N₂O emissions have fallen as agricultural productivity increased. This was largely achieved through government policies to reduce pollution in waterways and drinking water, which encouraged more efficient fertiliser use.

Other ways to reduce N₂O emissions from agriculture include:

  • better management of animal manure

  • applying fertiliser in a way that better matches the needs of growing plants

  • alternating crops to include those that produce their own nitrogen, such as legumes, to reduce the need for fertiliser

  • enhanced efficiency fertilisers that lower N₂O production.

Global nitrous oxide budget 2007-16. Adopted from Tian et al. 2020. Nature. Source: Global Carbon Project & International Nitrogen Initiative.

Getting to net-zero emissions

Stopping the overuse of nitrogen fertilisers is not just good for the climate. It can also reduce water pollution and increase farm profitability.

Even with the right agricultural policies and actions, synthetic and manure fertilisers will be needed. To bring the sector to net-zero greenhouse gas emissions, as needed to stabilise the climate, new technologies will be required.




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The Conversation


Pep Canadell, Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO; Eric Davidson, Director, Appalachian Laboratory and Professor, University of Maryland, Baltimore; Glen Peters, Research Director, Center for International Climate and Environment Research – Oslo; Hanqin Tian, Director, International Center for Climate and Global Change Research, Auburn University; Michael Prather, Distinguished Professor of Earth System Science, University of California, Irvine; Paul Krummel, Research Group Leader, CSIRO; Rob Jackson, Professor, Department of Earth System Science, and Chair of the Global Carbon Project, Stanford University; Rona Thompson, Senior scientist, Norwegian Institute for Air Research, and Wilfried Winiwarter, , International Institute for Applied Systems Analysis (IIASA)

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

‘Backwards’ federal budget: Morrison government never fails to disappoint on climate action



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John Quiggin, The University of Queensland

When it comes to action on climate change, Tuesday’s federal budget delivered by Treasurer Josh Frydenberg was a real – though not unexpected – disappointment which favoured polluting technologies over a clean energy future.

It included money to upgrade a coal-fired power station in New South Wales, and confirmed A$50 million previously announced to develop carbon capture and storage. The government will also spend A$52.9 million expanding Australia’s gas industry.

But investment in renewable energy was largely shunned. Notably, the government allocated just A$5 million for electric vehicles. It confirmed funding for the Australian Renewable Energy Agency (ARENA) for another decade, but the money is far less than what’s needed.

The COVID-19 pandemic has seen the Morrison government abandon long-held dogma on debt and deficits. However, the federal budget shows when it comes to climate and energy, the government is singing from the same old songbook.

Scott Morrison and Josh Frydenberg
On climate policy, the Morrison government is singing from the same old songbook.
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A techno-fix

The budget doubled down on the Morrison government’s rhetoric of “technology, not taxes”, by choosing preferred technologies for investment.

This “picking winners” approach would have some chance of addressing climate change if it were based on a comprehensive analysis of the best path to zero emissions. But instead, the government has largely made offerings at the altars of technologies worshipped by the conservative side of politics.

The government will spend an as-yet undisclosed sum, possibly A$11 million, to refurbish the Vales Point coal-fired power station. The commitment to this coal infrastructure, co-owned by prominent Liberal party donor Trevor St Baker, is a disgraceful misuse of public money. It will also do little to halt the steady decline of coal-fired power generation.




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As previously announced, the government will spend A$52.9 million to support the gas industry, which Frydenberg says will lower prices and support more manufacturing jobs. It includes money for gas infrastructure planning and to open up five gas basins, starting with Beetaloo Basin in the Northern Territory.

The budget confirms A$50 million for carbon capture and storage (CCS) to fund projects to cut emissions from industry. But proving the viability of large-scale CCS projects is extremely difficult, as experience in the United States and Canada has shown. In this context, allocating just A$50 million to get the technology off the ground is simply laughable.

History suggests the spending offers little return on investment. Research by the Australia Institute in 2017 revealed federal governments have spent A$1.3 billion in taxpayers’ money on CCS projects, with very little to show for it.

Vales Point coal plant
The budget contained spending to upgrade the Vales Point coal plant.
NSW Health/AAP

Renewables snubbed

Meanwhile, last night’s budget largely shunned investment in renewable energy.

The budget confirmed A$1.4 billion in ARENA funding for a further ten years, including a pretty paltry A$223.9 million over the next four years. Separately, the government will also seek to pass legislation to change ARENA’s investment mandate, enabling it to fund gas and carbon capture projects.

The government has allocated a tiny A$5 million towards electric vehicle development, including money towards a manufacturing facility in South Australia. It’s good to see electric vehicles on the government’s radar. But the commitment is dwarfed by investment overseas, including a reported US$300 billion set aside by global car makers over the next decade to bring electric vehicles to mass production.




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The measly spending on clean energy technology does not make economic sense. The renewable energy sector is standing by to slash emissions and deliver lower energy prices – if only the right policy environment existed.

The budget was also an opportunity for the government to ditch its irrational opposition to carbon pricing. Recent research has comprehensively shown carbon pricing slows growth in greenhouse gas emissions.

Vehement carbon pricing critics, such as conservatives Tony Abbott, Craig Kelly and Barnaby Joyce, are now either discredited or out of parliament altogether. And scores of countries around the world have implemented some form of price on carbon.

A global outlier

Most obviously, the budget was an opportunity to commit to net-zero emissions by 2050, as many developed countries have done.

The Morrison government has already used dodgy accounting tricks to meet Australia’s Paris Agreement commitment – reducing emissions by 26% on 2005 levels. The absence of a net-zero target suggests the government intends to allow emissions to grow indefinitely after 2030.

This approach is out of step with many of Australia’s international peers. Democratic presidential candidate Joe Biden, now the clear favourite to win the US election in November, is campaigning on what has been described as “the most aggressive climate platform” ever put forward by a presidential nominee.




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Biden wants the US to produce net-zero emissions by 2050. His US$2 trillion plan includes huge investments in clean energy research and development, and low-emissions infrastructure such as public transport and energy-efficient buildings. He has also promised a border tax levied on imports from countries without a carbon price.

Europe is well on the way to phasing out coal, and forging ahead with new carbon-free technologies to produce steel, cement and ammonia. The European Union has also said any free trade deal with Australia is contingent on our commitment to deep emissions abatement.

And in China, President Xi Jinping recently announced his nation will reach net-zero emissions by 2060.

Joe Biden
Democratic presidential candidate Joe Biden has an ambitious climate agenda.
Patrick Semansky/AP

We have no choice

The budget was a chance to reset Australia’s failed climate policy – an opportunity enhanced by the stimulus spending brought on by COVID-19.

Instead, we got a string of backward-looking gestures including subsidies for coal, another go at the failed technology of carbon capture storage and a continued push for gas.

Sooner or later, Australia will have to join the rest of the world in ending our reliance on carbon-based energy. The catastrophic bushfires of last summer proved this. And if we refuse to move, the rest of the world will force our hand.The Conversation

John Quiggin, Professor, School of Economics, The University of Queensland

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