Academic row over 'temperature neutrality' vs 'climate neutrality'

RTÉ News​

16 hours ago

Ireland's national climate objective is set out in the 2015 Climate Act.
It is to "pursue and achieve" and make the transition to "a climate resilient, biodiversity rich, environmentally sustainable and climate neutral economy" by the year 2050.
There are massive commitments packed into that single sentence, yet it is not really clear what precisely it means.
Ireland's climate scientists are now fighting over that issue.
The first bit is OK - climate resilience. We are going to have intense rain, more frequent and violent storms, bigger droughts and greater heat stress. Resilience means preparing to live with that.
The biodiversity bit is OK too. Protecting nature is not hard to understand and most people would sign up for that.
The third term – "environmentally sustainable". Some people think "sustainability" on its own is a bit of a wishy-washy term. But environmental sustainability is now commonly understood. Committees have been set up to focus on it in workplaces and communities all over the country.
But that last phrase in the national climate objective, the commitment to a "climate neutral economy". That is a different ball game altogether.
There is no agreement about what this entails, and a big academic row has now broken out among climate scientists about it.
They are at loggerheads over what exactly climate neutrality is and how it should be measured.
On one side is the Climate Change Advisory Council.
This is the independent statutory body of climate experts that advises the Government about climate matters.
It is their job to set Ireland's so-called "carbon budgets".
This involves calculating how much cumulative greenhouse gas emissions need to be restricted to, every five years, if the country is to stay within its legally binding climate commitments.
A huge amount of data and information, and some very important judgement calls, are needed for their calculations.
The data and information parts are complicated but straightforward enough.
Judgement calls however, are never straight forward and can be very controversial, as they are in this case.
This week, a group of climate scientists took a major swipe at a most important judgement call recently made by the Climate Change Advisory Council when setting Ireland's carbon budget for the years 2031 to 2035.
They accused the council of choosing to define climate neutrality in a way that confers a competitive advantage on Irish agriculture.
Their complaint, which is a serious one, is that the Government's key climate advisers are choosing now, for the first time, to substitute "temperature neutrality" for "climate neutrality" when calculating Ireland's carbon budget.
It means the Climate Change Advisory Council has told the Government it is OK to only ensure that by 2050 Ireland causes no additional warming to the earth's atmosphere.
This is not the same as delivering "net zero" emissions from Ireland by 2050 which is much harder to achieve.
The "net zero" approach puts the key emphasis on the quantity of greenhouse gas emissions.
It requires, among other things, enormous changes in farming practices, forestry and land use to ensure that absolutely all greenhouse gases still coming out of Ireland by 2050 are re-absorb by natural processes here.
Of course, the alternative "temperature neutrality" approach, now favoured by the Climate Change Advisory Council, aims to do everything possible to reduce greenhouse gas emissions.
But the difference with this approach is that the ultimate emphasis is to ensure the contribution Ireland is making to rising global temperatures is zero by 2050.
The council explained that it considered multiple definitions of what climate neutrality means before deciding that, for Ireland in particular, it had to mean ensuring temperature neutrality.
It also explained that in making this judgement call, it reflected on the national climate objective and was guided by the objectives of the United Nations Framework Convention on Climate Change.
It said the Paris Agreement's long-term temperature goal - which is to limit global warming to well below 2C and pursue efforts to limit warming to 1.5˚C - was also key in its deliberations.
Ireland produces nine times more beef and dairy output than it consumes. Because of this it has an unusual greenhouse gas emissions profile, with a far higher share of methane emissions than most other countries.
New Zealand is similar. But there are not many other places in the developed world where agriculture is so dominant.
Methane from agriculture is an enormously potent greenhouse gas. It is capable of trapping about 85 times more heat in the atmosphere than carbon dioxide over a short time frame.
After about 10 years however, methane dissipates. It breaks down and disappears from the atmosphere.
So, its impact on global temperature ceases in a few short years while the warming effect of carbon dioxide carries on for several hundred years.
All this means that a country with a huge agriculture sector can have an outsized impact in terms of limiting global warming by doing a relatively small amount of methane reduction.
It gives it more wriggle room if the main aim is to eliminate a nation's contribution to rising global temperature.
In some circumstances it could even enable a country to ease up on carbon emission efforts in sectors outside of agriculture and still ensure a lower contribution to the global warming potential of its national greenhouse gas mix.
It turns out that this is precisely the impact the Climate Change Advisory Council's adaptation of the temperature neutrality target has for Ireland.
The council itself has gone to some length to explain and document this impact.
It calculated that aiming for temperature neutrality instead of net zero emissions will enable Ireland to emit an additional nine million tonnes of greenhouse gases during the first five years of the next decade.
It also said it is entirely up to the Government to decide which sectors of the economy can share in that additional climate mitigation wriggle room, and by how much.
Its carbon budget proposal document says all this will be fine "provided the rest of the world follows an emissions pathway that can be considered compliant with the Paris Agreement long term temperature goals".
In essence what they are saying is that since most countries in the world do not have as large an agriculture sector as Ireland, or New Zealand, they are unlikely to choose the same temperature neutrality approach.
That is because there is no advantage for them in doing so. And if that remains the case then all will be well.
It is an approach that has startled the critics who have specifically highlighted the polar opposite argument – that it would be a disaster if every country followed Ireland and adopted temperature neutrality as their climate target.
The dissenters insist it would seriously jeopardise the Paris Agreement goal of limiting global warming to 1.5˚C.
These criticisms are outlined in a paper published in the journal Environmental Research Letters, by Dr Colm Duffy and David Styles of University of Galway, Dr Róisín Moriarty and Professor Hannah Daly of University College Cork, and Carl Doedens and Malte Meinshausen of the University of Melbourne.
They claim that Ireland's approach rewards modest cuts in methane emissions and serves to protect what they describe as "methane emissions privileges" at the expense of poorer nations.
In doing so, they say it locks in current inequalities in the global food system.
Their paper highlights that, by enabling Ireland to maintain a high share of global agriculture emissions, adopting the temperature neutrality target undermines the global transition to a sustainable and equitable food system.
They note too that it dramatically reduces the level of ambition needed for overall greenhouse gas emissions reduction.
Many might argue that the additional wriggle room it provides of nine million tonnes of emissions for Ireland spread out over a nine-year period does not sound particularly dramatic.
However, if lots of countries were to benefit from the same approach the impact could become dramatic very quickly.