Global greenhouse gas emissions have continued to increase, with unequal historical and ongoing contributions arising from unsustainable energy use, land use and land-use change, lifestyles and patterns of consumption and production, warns a new report published by the Intergovernmental Panel on Climate Change (IPCC). But there are “multiple, feasible and effective options to reduce greenhouse gas emissions and adapt to human-caused climate change”, according to the scientists, and these options are available now and need to be taken without delay. The synthesis report, released on March 20, summarises the UN body’s most up-to-date knowledge of science related to climate change, its impacts and risks, and mitigation and adaptation. It includes the contributions of the three IPCC working groups to the Sixth Assessment Report (AR6) and the findings of three special reports published between 2018 and 2022. The summary was prepared by 93 authors and approved during a week-long IPCC session in Interlaken in March. “Mainstreaming effective and equitable climate action will not only reduce losses and damages for nature and people, it will also provide wider benefits,” explained IPCC Chair Hoesung Lee. “This Synthesis Report underscores the urgency of taking more ambitious action and shows that, if we act now, we can still secure a liveable sustainable future for all.”

The scientists first looked at current status and trends with regard to our changing climate, pointing at the drivers of climate change and its impacts. Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperature reaching 1.1°C above pre-industrial levels, they find. Global net anthropogenic greenhouse gas emissions have reached 59 gigatonnes of carbon dioxide equivalent (GtCO2e) – about 12% higher than in 2010 and 54% higher than in 1990. In 2019, around 79% of global greenhouse gas emissions came from the sectors of energy, industry, transport and buildings together and the rest from agriculture, forestry and other land use (AFOLU). Global warming has resulted in more frequent and more intense extreme weather events such as heatwaves, heavy precipitation, droughts, and tropical cyclones. This has led to widespread negative impacts and related losses and damages to nature and people. According to the report, 3.3 to 3.6 billion people live in contexts that are heavily exposed to climate change. “Almost half of the world’s population lives in regions that are highly vulnerable to climate change,” said Aditi Mukherji, one of the authors. “Climate justice is crucial because those who have contributed least to climate change are being disproportionately affected,” she added. Increasing weather and climate extremes have exposed millions of people to acute food insecurity and reduced water security, hindering efforts to meet the Sustainable Development Goals. The main impacts are observed in many locations and/or communities in Africa, Asia, Central and South America, the world’s least developed countries, Small Islands and the Arctic. “In the last decade, deaths from floods, droughts and storms were 15 times higher in highly vulnerable regions,” Dr Mukherji explains. Indigenous Peoples, small-scale food producers and low-income households were affected most.

The authors also look at the pace and scale of what has been done so far. They establish that adaptation planning and implementation has progressed across all sectors and regions. Examples of effective adaptation options in the agricultural sector that are mentioned include “cultivar improvements, on-farm water management and storage, soil moisture conservation, irrigation, agroforestry, community-based adaptation, farm and landscape level diversification in agriculture, sustainable land management approaches, use of agroecological principles and practices and other approaches that work with natural processes”. The scientists also write that ecosystem-based adaptation approaches such as urban greening, restoration of wetlands and upstream forest ecosystems have been effective in reducing flood risks and urban heat. “Some land-related adaptation actions such as sustainable food production, improved and sustainable forest management, soil organic carbon management, ecosystem conservation and land restoration, reduced deforestation and degradation, and reduced food loss and waste are being undertaken, and can have mitigation co-benefits,” they add. But despite progress in some sectors, adaptation gaps exist, and will continue to grow at current rates of implementation. Maladaptation is happening in some sectors and regions and current global financial flows for adaptation are insufficient, especially in developing countries.

The next section of the report analyses future climate change, risks, and long-term responses. The scientists warn that continued greenhouse gas emissions will lead to increasing global warming and by 2030, global surface temperature in any individual year could already exceed 1.5°C relative to 1850-1900. Risks and projected adverse impacts and related losses and damages from climate change will intensify with every increment of global warming: They are higher for global warming of 1.5°C than at present, and even higher at 2°C. With further warming, climate change risks will become increasingly complex and more difficult to manage because risk drivers will interact. Climate-driven food insecurity and supply instability, for example, are projected to increase with increasing global warming, interacting with non-climatic risk drivers such as competition for land between urban expansion and food production, pandemics and conflict. Some future changes are unavoidable and/or irreversible but the good news is that they can be limited by a deep, rapid and sustained global reduction of emissions. However, adaptation options that are feasible and effective today would become constrained and less effective with increasing global warming and losses and damages would increase. All global modelled pathways that limit warming to 1.5°C involve rapid and deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade.

The final section of the report is dedicated to responses in the near term and stresses the urgency of near-term integrated climate action. The authors highlight that there is a rapidly closing window of opportunity. “Rapid and far-reaching transitions across all sectors and systems are necessary to achieve deep and sustained emissions reductions and secure a liveable and sustainable future for all.” These system transitions involve a significant upscaling of different mitigation and adaptation options. “Feasible, effective, and low-cost options for mitigation and adaptation are already available, with differences across systems and regions,” the report finds. There are many options in agriculture and land use that would provide benefits and that could be upscaled in the near-term across most regions. According to the report, conservation, improved management, and restoration of forests and other ecosystems offer the largest share of economic mitigation potential, with reduced deforestation in tropical regions having the highest total mitigation potential. “Effective adaptation options include cultivar improvements, agroforestry, community-based adaptation, farm and landscape diversification, and urban agriculture.” Some options, like the conservation of high-carbon ecosystems such as peatlands would deliver immediate benefits, while others, such as restoration of high-carbon ecosystems, take decades to show measurable results.

The authors also focus on equity and inclusion, governance and policies. They underline that prioritising equity, climate justice, social justice, inclusion and just transition processes is important. Integrating climate adaptation into social protection programs, including cash transfers and public works programs, is highly feasible and increases resilience to climate change, especially when supported by basic services and infrastructure. “The greatest gains in wellbeing could come from prioritizing climate risk reduction for low-income and marginalised communities, including people living in informal settlements,” said Christopher Trisos, one of the report’s authors. Finally, the authors highlight that effective climate action is enabled by political commitment, well-aligned multilevel governance, institutional frameworks, laws, policies and strategies. “Drawing on diverse knowledges and cultural values, meaningful participation and inclusive engagement processes – including Indigenous Knowledge, local knowledge, and scientific knowledge – facilitates climate resilient development, builds capacity and allows locally appropriate and socially acceptable solutions.” However, accelerated climate action will only come about if there is a many-fold increase in finance, says Trisos. Insufficient and misaligned finance will hold back progress. (ab)