Carbon budgets are Ireland's new mechanism for reducing damaging greenhouse gas emissions. These budgets, intended to halve annual emissions by 2030, have been acknowledged as among the most ambitious in the world. But the world is rapidly heating, causing irreparable damage to people and nature, and Ireland as a high-emitting country carries a disproportionate share of the responsibility.
Is our climate ambition enough, or do we need to do more?
Defining Ireland’s fair contribution to the global effort to limit greenhouse gas emissions is as much a question of justice as it is of science.
The Climate Act, which passed into law last year, requires that carbon budgets be consistent with our commitments under the Paris Agreement. In 2015, we agreed to hold the increase in the global average temperature to well below 2 degrees above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5 degrees along with 196 countries. The Act requires that carbon budgets should also take account of climate justice.
The Earth has already warmed by about 1.1 degrees. We know that global temperature rise is directly proportional to cumulative carbon emissions from climate science. Each tonne of carbon dioxide (CO2) emitted turns up the dial on the Earth’s proverbial thermostat permanently. Using this relationship, scientists have calculated different global carbon budgets corresponding to varying levels of future temperature rise.
If each country had emitted the same as Ireland on a per-capita basis, the world would already have warmed by a catastrophic 3 degrees
To limit warming to 1.5 degrees with a 50 per cent chance, we can emit another 500 billion tonnes of CO2, measured from the beginning of 2020, which is about 60 tonnes per person on the planet.
This remaining global carbon budget can be downscaled on a per-capita basis as a starting point for considering Ireland’s “fair share”. For five million people, this is about 300 million tonnes of CO2.
In Ireland, we emit about 45 million tonnes of CO2 each year from burning fossil fuels (for transport, heat, electricity and aviation); waste, industrial processes (including making cement) and drained peaty soils. If we maintained current emissions, we would blow past this fair share of the remaining global carbon budget by 2027. Any CO2 emitted after that point would have to be removed from the atmosphere, which is enormously difficult.
This approach ignores any historical responsibility for global warming, which is ethically debatable: If each country had emitted the same as Ireland on a per-capita basis, the world would already have warmed by a catastrophic 3 degrees.
Moreover, global methane emissions, the second-most harmful greenhouse gas, must fall by about 30 per cent by 2030 and 50 per cent by 2050 to meet the 1.5-degree goal.
From a pragmatic perspective, some could argue Ireland’s starting point is difficult because of national circumstances, justifying a higher share of the global budget. With no nuclear power, limited hydropower and tree cover, low carbon energy is challenging, and grass-based food production and peaty soils lead to high food and land emissions. Moreover, our past development pathway has locked us into car dependence and high fossil fuel use.
However, it is difficult to argue for an increased share of the global carbon budget from a climate justice perspective. The science has been settled for 30 years, and decision-makers have known about the consequences of locking the country into an unsustainable pathway.
Ireland can contribute to the global climate mitigation effort by continuing to research and roll out low-carbon technologies and sustainable solutions
Far more could have been done to limit greenhouse gas emissions, despite national circumstances. Even in the seven years since Ireland signed up to the Paris Agreement, sustainable solutions have not been rolled out quickly enough: CO2 emissions have not fallen (except for a temporary drop in 2020 due to Covid measures), and methane emissions have continued to rise.
Moreover, it would be unjust to argue for a larger share of the global carbon budget: It would mean a smaller allocation for developing countries who have done little to cause climate change and are highly vulnerable to its impacts.
Along with rapidly reducing greenhouse gas emissions, Ireland can contribute to the global climate mitigation effort by continuing to research and roll out low-carbon technologies and sustainable solutions. This will help bring down costs globally and support developing countries to leapfrog the high-carbon development pathway we have taken.
The remaining carbon budget is small and diminishing very rapidly. New national stringent carbon budgets are an acknowledgment that every tonne of greenhouse gases emitted permanently damages the Earth’s systems. If we are to keep the world at a safe temperature, the urgency of deep emissions cuts is clear.
Dr Hannah Daly is a lecturer in sustainable energy systems modelling at University College Cork