Key lessons from the latest IPCC Report
25 March 2022
The Sixth Assessment Report from the UN’s Intergovernmental Panel on Climate Change (IPCC) assessed the impacts, adaptation, and vulnerabilities of climate change, and I am privileged to be one of the 270 scientists and researchers who co-authored it. 
The latest report provides a sobering assessment of how current global warming of 1.1°C is already impacting natural and human systems, and how our ability to respond will be increasingly limited with every additional increment of warming. Here, I reflect on the key findings and lessons from the report, and how they relate to the Water Security Hub’s research programme.
Risks will be magnified if warming is unchecked
Since the previous IPCC Report on impacts and adaptation (in 2014), climate extremes - heatwaves, droughts, wildfires - have increased in frequency and intensity, impacting people and ecosystems around the world.
The report assesses, with high confidence, that climate change has affected the physical aspects of water security, exacerbating existing water-related vulnerabilities caused by other socio-economic factors. Extreme weather events, including floods and droughts, have become more likely. While these impacts will vary regionally, between 3-4 billion people are projected to be exposed to physical water scarcity at 2°C and 4°C global warming levels respectively. Direct damages from flooding are projected to increase by 4 to 5 times at 4°C, compared to at 1.5°C. Such a significant change to hydrology is projected to compromise the efficacy of water, sanitation, and hygiene (WASH) services and delay progress in improving water-related public health.
The Hub has an extensive programme of research studying water risks, covering flooding, drought, water quality, sanitation, and public health. During our webinar series we have been sharing understanding and findings from across our case study sites. These local and catchment scale assessments help connect the global context of climate change to local risks, and action to adapt.
There are limits to adaptation
Adaptation to manage the impacts and risks of climate change works. However, the effectiveness of future projected adaptations in reducing risks falls sharply beyond 2°C global warming, underscoring the need to achieve the Paris Agreement. At global warming levels beyond 1.5°C, the biophysical limits to adaptation may be reached due to limited water resources; small regions dependent on glaciers and snowmelt are especially vulnerable. Many limits to adaptation are human obstacles, for example insufficient finance and poor planning, which could be addressed through more inclusive governance.
Adaptation cannot prevent all climate impacts, which are unequally distributed around the world. Mitigation of greenhouse gases and limiting global warming is therefore an essential part of risk management. Understanding interactions, and potential synergies and tradeoffs between different adaptation choices, and other priorities such as the SDGs, is central to the Hub’s systems approach.
‘Maladaptation’ can compromise delivering SDG6
The IPCC Report highlights examples and evidence of adaptation actions that compromise other important objectives. These include reducing greenhouse gases, delivering SDGs, or deepening existing inequities. This is referred to as “maladaptation”. For example, measures such as bio-energy, desalination, afforestation, carbon capture, and storage can have a high-water footprint.
The water intensity of climate action must be achieved in an equitable and just manner, whilst also enhancing water security and supporting sustainable development. The IPCC Report also highlights that many of the countries and social groups most at risk of climate change impacts don’t have the capacity to respond. For the first time, the importance of indigenous and local knowledge – alongside technical knowledge – was recognised as key to tackling climate change. Moreover, cooperation and coordination amongst all stakeholders, including women and marginalised groups, is required for effective climate resilient development. The Hub’s Collaboratories (Collaborative Laboratories) are doing just this – providing a space for all voices to be heard, and enabling creative solutions to water security to emerge that are appropriate to the local context.
Cities are a challenge – and an opportunity
Over half the world now lives in urban areas. The IPCC Report states that more than one billion people in low-lying settlements are at risk of flooding and sea-level rise, while 350 million urban residents live with the threat of water scarcity. Climate change is driving other impacts such as extreme temperatures and worsening other environmental problems in cities, such as air pollution.
Yet because of their concentration of people and activity, urban areas are also sites of opportunity. The IPCC report maps a wide range of options for urban adaptation, ranging from flood defence and water infrastructure, nature-based solutions and spatial planning, social policy measures such as social safety nets, insurance, and other support. The Hub’s work on water-sensitive planning is developing new approaches to design cities that are more water secure. The launch of a new national Centre for Water Studies at SPA New Delhi – a first in India – is enhancing the capacity of practitioners working in water-related organisations, through the provision of training that integrates water security and sustainable urban development
The window of opportunity is closing, rapidly
Perhaps the most important underlying insight from the IPCC Report is the need to accelerate action. Delivering climate resilient development is already a challenge; impacts will continue to increase if global warming is not tackled. Each increment of global temperature rise, however small, increases impacts.
Without current adaptation efforts, the report shows that the impacts today would have been substantially worse, but - crucially - we are not adapting fast enough to keep pace with accelerating climate change. Adaptation has typically been small-scale and sector-specific, rather than the sort of systemic changes the Hub is exploring.
The effectiveness of some adaptation actions are reduced beyond 1.5°C; some regions and systems may suffer irreversible changes beyond this. This underscores the urgency for climate action, and the need to couple adaptation measures with greenhouse gas emission reductions to enable climate resilient development. The IPCC Report shows that systems transformations are required involving adequate financing, integration of grey and green infrastructure, inclusive governance, transparency in decision making, and the participation of a wide range of people and groups.
It is reassuring that the Hub’s programme is making such a positive contribution to support climate action. However, the IPCC’s report reminds us that the clock is ticking, and that both research and action must be accelerated.
 Richard Dawson was a Lead Author of Chapter 6: Cities, Settlements and Critical Infrastructure, a Coordinating Lead Author of the Cross-Chapter Paper on Cities and Settlements by the Sea and a Contributing Author to Chapter 16: Key Risks Across Sectors and Regions.