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

Without immediate and deep carbon emissions reductions across all sectors, limiting global warming to 1.5 degrees “is beyond reach”, the UN Intergovernmental Panel on Climate Change (IPCC) warns in its latest report.

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 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 and deployment of CO2 removal from the atmosphere, though this technology is unproven – with no indication of cost.

“It’s now or never, if we want to limit global warming to 1.5 degrees,” said report co-chair Prof Jim Skea. “Without immediate and deep emissions reductions across all sectors, it will be impossible.”

The report outlines some positive trends, notably in 2010-2019 average annual global emissions were at their highest levels in human history but the rate of growth has slowed, the IPCC report notes.

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,” he added.

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.

The WG3 report is the third instalment of the IPCC’s sixth global assessment (AR6), which will be completed later this year.

“Having the right policies, infrastructure and technology in place to enable changes to our lifestyles and behaviour can result in a 40-70 per cent reduction in greenhouse gas emissions by 2050. This offers significant untapped potential,” said WG3 co-chair Priyadarshi Shukla.

“The evidence also shows that these lifestyle changes can improve our health and wellbeing.”

The report underlines the critical role of cities and urban areas in offering significant opportunities for emissions reductions. “These can be achieved through lower energy consumption (such as by creating compact, walkable cities), electrification of transport in combination with low-emission energy sources, and enhanced carbon uptake and storage using nature.”


There are options range across established, rapidly growing and new cities, it concludes.“We see examples of zero energy or zero-carbon buildings in almost all climates,” Prof Skea said, but “action in this decade is critical to capture the mitigation potential of buildings.”

Climate change is the result of more than a century of unsustainable energy and land use, lifestyles and patterns of consumption and production. This report shows how taking action now can move us towards a fairer, more sustainable world,” he added.

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.

Temperature stabilisation

Global temperature will stabilise when carbon dioxide emissions reach net zero, the IPCC predicts. For 1.5 degrees, this means achieving net-zero carbon dioxide emissions globally in the early 2050s; for 2 degrees, it is in the early 2070s.

Investment gaps

The report shows that while financial flows are a factor of three to six times lower than levels needed by 2030 to limit warming to below 2 degrees, there is sufficient global capital and liquidity to close investment gaps.

However, the IPCC says “it relies on clear signalling from governments and the international community, including a stronger alignment of public sector finance and policy”.

“Despite the triple crisis of the war in Ukraine, the pandemic, and rising inflation, the world’s governments have signed-off the definitive common guide to tackling climate change,” said Prof Simon Lewis of University College London. “This report shows how countries can meet the obligations they signed in Paris in 2015 and reaffirmed in Glasgow late last year. They have no excuses now. The scientists involved have done an incredibly impressive job in getting this over the line in the circumstances.”

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.


“In any case we must also speed up the deployment of zero-carbon alternatives to fossil fuels, the cost of which have fallen spectacularly over the past few years… Europe has learned over the past few months that the dependence on fossil fuels also threatens energy security and affordability.”

Lead author Prog Linda Steg said their assessment report shows many people care about nature, the environment and are motivated to engage in climate actions. “Yet they may face barriers to act, which can be removed by actions, for example, by industry, businesses, and governments.”

“Many governments are struggling with the question whether people would support changes. This assessment report shows that public acceptability is higher when cost and benefits are distributed in a fair way, and when fair and transparent decision procedures have been followed,” she added.

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