Devastating flooding that pummeled Spain, six storms hitting the Philippines in a matter of weeks, disastrous hurricanes in the US. All of these extreme weather events took place just weeks before—and in some cases, occurred during—the COP29 meetings this year in Azerbaijan.
Ahead of the meeting in Baku, a group of globally renowned scientists teamed up to synthesise the most pivotal developments in climate change research published over the previous 1 and a half years. The findings are summarised in 10 insights, for which they also provide a set of policy implications. Since 2017, the annual publication, called the 10 New Insights in Climate Science, serves as an important source of information for decision-makers at the COP negotiations and in the successive months.
“The urgency to respond to climate change has never been clearer,” said Peter Schlosser, Vice President and Vice Provost of Global Futures, Arizona State University, and co-chair of The Earth League. “Every degree of warming, every delay in action, accelerates the transition from climate crisis to climate catastrophe. We have to translate our existing knowledge to action much faster to preserve Earth’s life-supporting systems and bring humanity back to a state where it is in balance with the Earth system on which it depends.”
As the meetings in Baku draw to a close, here’s what scientists have flagged this year as some of the most pressing findings that deserve the world’s attention.
Methane Must Be Monitored
One of the most important parts of this year’s analysis focused on methane emissions. Atmospheric methane levels have grown since 2006, with the last five years showing the fastest increase ever since records began. Fossil fuels, livestock, and waste are the main drivers of methane emissions. In addition, emissions also come from natural sources and are expected to be further amplified by climate feedback mechanisms. The analysis finds that sufficient information on methane sources and monitoring capacity is available, but enforceable policies to drive reductions are vital.
Illustration: Nicole Kelner
Aerosols Need More Study
Aerosols—very small particles that have big implications for the climate—can come from natural sources, like volcanoes, and human sources, such as from burning fossil fuels which cause air pollution, a threat for human health. Successful policies have led to a progressive decrease worldwide in air pollution. Aerosol reductions have also demonstrated the potent effect these small particles have on the climate, influencing global and regional temperature, precipitation and circulation. The strong cooling effect they bring also decreased, showing, or “demasking”, the full warming impact of accumulated greenhouse gases. There’s a lot we still don’t know about the interaction between aerosols and warming. For this reason, the analysis says that advances in research are essential, and should also inform mitigation and adaptation strategies.
Heat Is Changing the Human Condition
The science is clear: human influence has warmed the atmosphere, ocean and land. The global surface temperature in 2023 was 1.43°C above the 1850-1900 average, of which 1.31°C was human induced-warming. The 10 Insights in Climate Science explain how increasing heat and humidity induced by climate change are pushing more people outside the climatic conditions ideal for human physiology—what’s known as the human climate niche. Some 600 million already live outside of this niche; for each degree of warming, an estimated 10% of the global population will join them. Most of the exposed regions are concentrated in the Global South.
More specifically, the report highlights how urging temperatures are also affecting maternal and reproductive health, increasing pregnancy loss, preterm birth and other risks for both mothers and babies. This gendered issue particularly affects climate-vulnerable regions and women at low-income and educational levels.
“Preparedness for heat extremes, including early warning systems, must be a priority at the national and regional scale,” said Prof. Dr Jemilah Mahmood, Executive Director of the Sunway Centre for Planetary Health. “Without action, the consequences could be catastrophic. Without systemic shifts, future generations will be impacted.”
The Amazon Must Be Preserved
The Amazon rainforest is host to around 10% of the planet’s terrestrial biodiversity and more than 400 ethnicities of Indigenous peoples and local communities. It also regulates temperature and precipitation, sequesters carbon, and recycles around 16–22% of Earth’s freshwater, affecting the planetary energy balance. But human activities, including deforestation, road construction, etc., are putting the Amazon’s stability at risk, negatively impacting the key processes it regulates, with significant implications for the entire planet. The authors argue developing regional and local plans in collaboration with local communities and Indigenous people is key to preserving this crucial natural resource.
The Ocean Is Cause For Concern
Over the past year, global sea surface temperature has reached unprecedented levels, breaking records not only in the tropical Pacific due to El Niño, but also in the North Atlantic, Gulf of Mexico, Caribbean, and the Southern Ocean in the Antarctic. Studies have found that the global economic costs of El Niño, the warming phase of the natural climate phenomenon El Niño-Southern Oscillation (ENSO), are much higher than previously thought. The report also focuses on the Atlantic Meridional Overturning Circulation (AMOC), a key ocean current system that brings warm water north and cold water south, which may slow down or collapse sooner than earlier models projected, and calls for improved models and longer, more accurate observational records to reducing uncertainties in projections.
“Our oceans are hotter than ever now, leading to disruptions in global weather patterns and marine ecosystems,” said Wendy Broadgate, Global Hub Director at Future Earth. “We’re witnessing increasingly severe storms and widespread coral bleaching. This year’s report provides crucial scientific insights to underpin commitments by world leaders at COP29 to significantly step up their ambition. It’s only by reducing greenhouse gas emissions that we can reduce further risks and costs to societies and ecosystems.”
Protecting Infrastructure and Cities With New Tech and Systems
Critical infrastructure, the analysis points out, is essential for societies and, at the same time, very vulnerable to climate hazards. The authors argue that artificial Intelligence (AI) tools can boost their resilience to climate change.
Cities are also highly vulnerable to climate hazards: according to the report, around 80 of the 100 fastest growing cities in the world–which are also classified at high risk of climate change—are in Asia and Africa. Yet, only a few cities include effective mitigation and adaptation in their action plans. The study proposes the social-ecological-technological systems (SETS) approach to help guide climate-resilient development.
Fairness Is Key—in Supply Chains and Policies
Renewable energy plays a key part in reaching net zero targets. As demand for energy transition minerals (ETMs) rises, supply chain risks, geopolitical tensions, and socio-environmental impacts concentrated in the Global South are expected to increase. The analysis calls for closing governance gaps in the ETM global value chain to reach a just and equitable energy transition.
A just transition needs clear communication. Policies are the core of climate action. Acceptance and resistance to climate policies depend on a myriad of factors, from social norms, to cultural identities, to economic conditions. Research has found fairness to be a central determinant of acceptance and resistance.
“Ignoring citizens’ readiness and needs when designing and implementing climate policies will ultimately lead to many missed opportunities in the near term through undermined and ineffective climate policy,” said Prof. Joyashree Roy from the Asian Institute of Technology. “According to the IPCC, 40% of the world are already highly vulnerable to the ever-rising global temperatures. Policymaking in every country must be inclusive and carefully navigate a variety of socio-economic factors, to enhance policy acceptability.”
The Time to Act Is Now
As negotiations continue this week, the science is clear: emissions must to be reduced. Reductions can no longer wait. At current emissions levels, the carbon budget for a 50% likelihood to limit global warming to 1.5°C will be exhausted in 6 years. Science is urging countries to ramp up ambition in their new Nationally Determined Contributions (NDCs) due in early 2025. But, sufficient funding is a prerequisite for climate action: experts recommend governments should focus on mobilising $1 trillion per year for developing countries by 2030.
“This report confirms that the world faces planetary scale challenges, from the rise of methane emissions to the vulnerability of critical infrastructure,” said Prof. Johan Rockström, co-chair of The Earth League. “It shows that rising heat, ocean instability and a tipping of the Amazon Rainforest could push parts of our planet beyond habitable limits. Yet, it also provides clear pathways and solutions, demonstrating that with urgent, decisive action, we still can avoid unmanageable outcomes.”
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