Climate change report: ‘It’s now or never if we want to limit global warming to 1.5 degrees’

Irish climatologist says report gives countries ‘an F or E minus’ in terms of performance

The world is heading in the wrong direction on carbon emissions in spite of a narrowing window of less than a decade to contain a catastrophic rise in global temperatures, according to climatologist Prof Peter Thorne of Maynooth University.

Commenting on the latest part of a global assessment by the UN Intergovernmental Panel on Climate Change (IPCC), he said: “If the report were to constitute our global school report card we would, sadly, have been given an F, or perhaps being charitable an E minus.

“We are not on track to limit warming to 1.5 degrees. In fact we are still heading fundamentally the wrong way. Average annual emissions of heat trapping gases during 2010-2019 were the highest in human history, despite our knowledge of the harm they are doing,” said Prof Thorne who was a lead author on the first part of the report published last August.

Many of the options were “win-win activities that would bring economic and social benefits while simultaneously reducing the harm to the climate. Our governments must be brave”, he said.


There are options in all sectors to at least halve emissions by 2030, the IPCC concludes, but limiting global warming “will require major transitions in the energy sector... a substantial reduction in fossil fuel use, widespread electrification, improved energy efficiency, and use of alternative fuels – such as hydrogen”.

Compiled by leading climate scientists, economists and social scientists, the report, published on Monday, underlines the need for immediate action: “The next few years are critical. In the scenarios we assessed, limiting warming to around 1.5 degrees requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by 43 per cent by 2030; at the same time, methane would also need to be reduced by about a third.”

Even if this is achieved “it is almost inevitable that we will temporarily exceed this temperature threshold [a key Paris Agreement target] but could return to below it by the end of the century”.

Previous IPCC reports have highlighted that exceeding 1.5 degrees risks unleashing a far more severe climate change effects on people, wildlife and ecosystems.

End of the century

The latest report shows warming will likely exceed 1.5 degrees by mid century, while the best the world can now aim for is to bring down the temperature before the end of the century through natural and artificial means of removing carbon dioxide from the atmosphere. This would entail accelerating development of CO2 removal from the atmosphere, though this technology is unproven.

The report outlines some positive trends: In 2010-2019 average annual global emissions were at their highest levels in human history but the rate of growth has slowed. In addition, there is increasing evidence of effective but uneven climate action with “at least 18 countries have sustained emission reductions for longer than 10 years”.

Ireland is among countries where overall emissions have continued to rise.

Since 2010, there have been sustained decreases of up to 85 per cent in the costs of solar and wind energy, and batteries. “An increasing range of policies and laws have enhanced energy efficiency, reduced rates of deforestation and accelerated the deployment of renewable energy,” it finds.


"We are at a crossroads. The decisions we make now can secure a liveable future. We have the tools and know-how required to limit warming," said IPCC chair Hoesung Lee.

“There are policies, regulations and market instruments that are proving effective. If these are scaled up and applied more widely and equitably, they can support deep emissions reductions and stimulate innovation.”

The summary for policymakers of the Working Group 3 report on mitigation of climate change was signed off after protracted negotiations over the weekend by 195 member governments of the IPCC.

Reducing emissions in industry will involve using materials more efficiently, reusing and recycling products and minimising waste. For basic materials, however, including steel, building materials and chemicals, low- to zero-greenhouse gas production processes are still at a pilot to near-commercial stage. The sector accounts for about a quarter of global emissions.

“Achieving net zero will be challenging and will require new production processes, low and zero emissions electricity, hydrogen, and, where necessary, carbon capture and storage,” it says.

Land use

Agriculture, forestry, and other land use which contributes 22 per cent of global emissions can provide large-scale emissions reductions “and also remove and store carbon dioxide at scale”, the IPCC says. “However, land cannot compensate for delayed emissions reductions in other sectors.”

Well-designed land-based mitigation options to remove carbon can also benefit biodiversity and ecosystems, help adapt to climate change, secure livelihoods, improve food and water security. Options include protecting and restoring natural ecosystems such as forests, peatlands, wetlands, savannas, and grasslands.

Leading UK climate specialist Prof Bob Ward said: "This report lays out starkly how much trouble the world is now in because governments have been too slow to recognise and respond to the threat from climate change driven by greenhouse gas emissions."

The previous IPCC report published in February was very clear about the huge scale of the potential impacts on lives and livelihoods worldwide if global temperature rises by more than 1.5 degrees, he noted.

“But this new report shows that warming will likely exceed 1.5 degrees by about the middle of this century, and the best we can now aim for is to bring down the temperature before the end of the century through natural and artificial means of removing carbon dioxide from the atmosphere. This means we must accelerate the development and deployment of carbon dioxide removal, even though we are not yet sure of its feasibility and cost at large scale,” Prof Ward added.

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times