Greenhouse gas (GHG) emissions have reached an all-time high with marked acceleration in the past two years threatening to push the world into “unprecedented” levels of global heating, leading climate scientists have said.
Analysis by the 50 scientists from Ireland and the UK issued yesterday shows a record level of carbon was emitted each year of the past decade, equivalent to 54 billion tonnes of carbon dioxide, with human-induced warming averaging 1.14 degrees.
The remaining “carbon budget” – how much carbon dioxide can be emitted to have a better than 50 per cent chance of holding global warming to 1.5 degrees (a key Paris Agreement target) – has halved over three years.
Their data was published to coincide with UN climate negotiations in Germany this week. Climate experts under the Intergovernmental Panel on Climate Change (IPCC) are meeting in Bonn to prepare for COP28 next December when a stocktake of progress towards keeping global warming to 1.5 degrees by 2050 will be conducted.
It is critical that policymakers and the public are made aware “how quickly we are changing the climate through our collective activities”, said Prof Peter Thorne, IPCC author and director of ICARUS climate research centre at Maynooth University, who contributed to the research.
“Already since the IPCC assessment of the physical science basis [of climate change] in 2021 key numbers have changed markedly and we remain well off track globally to avert warming above 1.5 degrees,” he said.
Reaching 1.5 degrees would bring “a whole world of hurt” he predicted, with unimaginable levels of hurt beyond that level of warming.
Prof Thorne said: “The deterioration in these key metrics of climate change at such a pace is consistent with expectations of an accelerating climate system response as we continue to increase global GHG emissions.”
The latest data “increases the urgency of COP28, if we have any hope of ‘keeping 1.5 alive’ although, in reality, the best we can now hope for is probably 1.5 degrees with little or low overshoot”.
“If we pass 1.5 the next best thing we can do is stop warming reaching 1.6 and so on and so forth. At no point should we throw up our hands in despair. Every saved emission is a reduced climate impact,” he said.
On implications for the Government, Prof Thorne said: “The findings increase yet further the urgency of meeting our legal obligations under the amended Climate Act. That means taking seriously recent warnings from EPA and others that we are currently off-course and redoubling efforts to get back on track. Ultimately the climate system will respond to our collective emissions and does not care a whit about special pleading from every sector as to why they can’t reduce emissions.”
The EPA projected last week that Ireland would achieve a reduction of only 29 per cent in emissions by 2030, far short of a legally-binding target of 51 per cent, a core part of the Government’s climate policy.
Given the speed at which the global climate system is changing, the scientists say governments, policymakers, climate negotiators and civil society groups need to have access to up-to-date and robust scientific evidence on which to base decisions. They have launched the Indicators of Global Climate Change project to update on indicators annually with a view to more timely action. The IPCC is the most authoritative source of research on climate but turnaround time for its major assessments is five to 10 years.
“This is the critical decade for climate change. Decisions made now will have an impact on how much temperatures will rise and the degree and severity of impacts we will see as a result,” said co-ordinator Prof Piers Forster.
Long-term warming rates are at a long-term high, caused by record-breaking levels of emissions but there is evidence the rate of increase in carbon has slowed.
“Even though we are not yet at 1.5 degrees warming, the carbon budget will likely be exhausted in only a few years as we have a triple whammy of heating from very high CO2 emissions, heating from increases in other GHG emissions and heating from reductions in pollution,” Prof Forster said.
“If we don’t want to see the 1.5 degree goal disappearing in our rear-view mirror, the world must work much harder and urgently at bringing emissions down,” he said.