Megha Kaveri

We live at a time in which articles, pictures and videos of extreme weather events dominate the media and our memories. From flash floods and rapidly advancing cyclones to wildfires and heatwaves, the effects of climatic extremes are broad and devastating.   

Extreme weather events are defined as discrete episodes of extreme weather or unusual climate conditions, often associated with deleterious impacts on society or natural systems, defined using some metric to characterize either the meteorological characteristics of the event or the consequent impacts. 

While scientists have attributed a part of the current spate of extreme weather events to El Niño, a much bigger driver of these events is climate change. Additionally, scientists have also warned that in the coming years, these extreme weather events are only likely to continue and worsen.  

Extreme weather events, while causing severe damage to people’s lives and property, also have lasting impacts on food production, public health, education, ecology and biodiversity, geography, and indigenous communities. To protect the planet and communities from perennial damage, it is crucial to empower decisionmakers with the right information. The evidence that will form the basis of such information is built by scientific research.  

Robust science and research will contribute to improving the existing knowledge about climate and extreme weather events which, in turn, will help stakeholders to achieve climate-related SDGs.  

Is the scientific community doing enough to understand extreme events? 

Extreme weather events, in the past, have taken us by surprise, both in intensity and in their impacts, says Dr Gabi Hegerl, professor of climate system science at the School of Geosciences, University of Edinburgh. She adds that the surprise element in these events highlights the need to better understand what drives them.  

“Methods to determine rarity of such events and identify analogues from past to future need to be further developed – we are still challenged when it comes to multi-variate extremes,” she points out.  

In addition to the surprise element, extreme weather events are also harmful to society and a threat to development, especially for vulnerable people. It is hence more relevant to know how these events affect the society, economy, and human settlements, Dr Amadou Gaye, professor at the University Cheikh-Anta-Diop of Dakar (UCAD), says. “We need to better forecast them for early warning and for mitigating their impacts.” 

Both the experts agree that the community needs to do more to study and forecast climate extremes better, particularly in places where capacities are low.  

What is the way forward? 

With the frequency of extreme weather events set to increase in the coming years, looking into possible solutions is imperative. Since the impacts of such events are both immediate and long-term, the solutions must also cover a broad base by focussing on interdisciplinary research and increased collaboration between researchers from across the world.  

“Working with colleagues worldwide ensures that a topic gets robustly addressed, work gets constructively critiqued and that new methods to improve analyses are shared. This has worked excellently for detection and attribution, and is now happening for extremes,” Dr Hegerl reveals.  

Global research collaboration also helps in building capacity in vulnerable climatic regions. Dr Gaye says that Africa, despite being an important region in the tropics, has much less of the information needed to face extreme events and also less research because there are only a few scientists working on these topics in or outside the continent.  

“The paradox is that there is an imperative need to understand the climate in this very important part of the tropics better. We also need to develop more interactions between disciplines because the solutions are not only (based) on the development of the physical science but also on how science and technology can be used to solve problems.” 

To foster higher collaboration and build capacities, funding is key.  

“Extremes research is important and rapidly developing and needs funding, and doing so will save society from costly mal- or under adaptation,” says Dr Hegerl. She adds that while some funding agencies do focus on solutions and adaptation measures, neglecting physical climate science is risky. “Not connecting it with its impacts is a missed opportunity.” 

Increased funding support could also enhance capacity-building in the South and underrepresented regions in the global scientific community, Dr Gaye asserts. “We need to seriously address the production and availability of data to academic communities in the South.” 

Dr Sonia I. Seneviratne 

Professor for Land-Climate Dynamics, ETH Zurich, and IPCC Working Group I Vice-chair

This summer has been like no other. It was the warmest on record, with the month of August being the first to reach an anomaly of 1.5°C above the pre-industrial average for 1850-1900. Forest fires in Canada induced an unprecedented loss of forests, leading to CO₂ emissions about triple of the country’s annual carbon footprint. Heatwaves affected North America, Europe, and Asia, and torrential rain fell in several countries across the Mediterranean in September. All these extreme conditions were made more probable due to human-induced climate change and will become increasingly frequent and intense with additional emissions of CO₂ in the atmosphere, as summarized in the latest assessment of the Intergovernmental Panel on Climate Change (IPCC). 

What can we do as a climate research community in the face of the mounting extremes resulting from our footprint on the climate system? 

First, it is essential to monitor these changes to properly inform the public and policymakers on the current state of the climate system. In addition to short-term evaluations provided for single events by the World Weather Attribution (WWA) initiative and the in-depth and comprehensive assessments provided every 7-8 years by IPCC based on an extensive review of the literature, it would be valuable to provide yearly and comprehensive reports on reported climate extremes and their possible attribution to human-induced climate change. Such assessments are planned within a new World Climate Research Programme (WCRP) initiative, the “Global Extreme Platform” (GEP), which is part of the Regional Information for Society (RIfS) core project.  

Second, the relevance of climate extremes for adaptation and mitigation pathways needs to be assessed in more depth in the climate research community and in the resulting IPCC assessments under the new IPCC 7th assessment cycle. In particular, the emissions pathways underlying the climate projections assessed in the IPCC reports and computed as part of the WCRP CMIP experiments, do overall not consider possible effects of climate extremes for society. This is of strong concern for the realism of such emissions scenarios, both for ambitious pathways relying for instance on large-scale afforestation (but which could be threatened by enhanced fire weather occurrence), as well as for high-emissions pathways assuming that the world economy would not be affected by an increasing occurrence of record-shattering climate extreme events. 

Finally, we also have a responsibility as a research community to help contribute to less CO₂ accumulation in the atmosphere. Both as part of the WCRP and the IPCC communities, it would be valuable to have reflections on how to continue to do effective science and science assessments, while ensuring that leading climate institutions are themselves on an emission pathway consistent with a stabilization of global warming at 1.5°C. The first essential step for achieving this goal is to halve global CO₂ emissions until 2030.