Tackling the twin biodiversity and climate crises: Twin crises, shared solutions

09 January 2026

Part two of a collaborative five-part series between CIWEM and the Chartered Institute of Ecology and Environmental Management (CIEEM) which highlights shared insights, innovations and ambitions from those working in water, ecology and environmental management

The World Economic Forum (WEF) have declared that biodiversity loss and climate change are among the most significant threats to humanity over the next decade – and both are accelerating at an alarming rate. Biodiversity loss undermines food security, medicine and the ecosystems that support over half of global GDP. Climate change brings rising seas, extreme weather and soaring temperatures. Too often, these crises have been treated separately – but they are deeply intertwined.

Climate change depletes ecosystems, while biodiversity loss reduces carbon sequestration, further intensifying climate impacts. Yet nature itself may hold the key to reversing this cycle – offering solutions that benefit both people and the planet.

Protesters highlight the significance of the climate and biodiversity crises – action is needed now. Source: Earth.com

What is climate resilience – and why nature holds the key

Climate resilience can be defined as the adaptation of businesses, society, the environment and infrastructure, to mitigate the impacts of, and thrive, in the face of climate change. The concept emerged in the late 20th century as societies sought ways to adapt to a changing climate, but ecosystems can’t evolve fast enough to keep pace. Since 1970, monitored species populations have declined by 73%, according to the World Wildlife Fund (WWF).

Resilience is now essential – not just for nature, but for communities and economies. Themes like green infrastructure, Nature-Based Solutions (NBS) and climate-resilient development are increasingly embedded in policy and practice. When guided by collaboration and data, these innovative approaches offer a more sustainable future.

Nature-Based Solutions (NBS)

Coined by the World Bank in 2008, NBS are eco-positive, cost-effective strategies that harness natural processes to address environmental challenges. They protect and restore ecosystems to tackle flooding, air pollution and habitat loss—delivering benefits for both biodiversity and human wellbeing.

In England, the Norfolk Water Strategy Programme found that every £1 invested in NBS yields £6.70 in benefits. Across Western Europe, $181 billion in forest restoration could prevent $926 billion in land degradation costs—a fivefold return on investment (ROI). A strong ROI for NBS is vital for attracting investment given the financial challenge of becoming climate resilient. For example, Anglian Water Services alone have committed £11 billion towards climate and social resilience over five years, including £1 billion for two new reservoirs in the East of England.

NBS in action: from estuaries to urban streets

The Environment Agency’s (EA) 2025 position statement champions NBS as essential for flood management, climate adaptation and nature recovery across England. A leading example is the Thames Estuary project, which uses managed realignment and habitat restoration to recreate wetlands, mudflats, and saltmarshes—offering natural flood defence, improved water quality, and enhanced biodiversity. As Europe’s largest coastal habitat restoration, it illustrates how NBS can complement traditional engineering for sustainable, cost-effective outcomes.

Urban NBS are increasingly vital as cities face mounting climate pressures. The EA highlights the need for strong policy and collaboration across government, communities and businesses to scale these solutions. NBS deliver environmental, social and economic benefits that support long-term sustainability. London’s approach sets a precedent for other cities pursuing nature-positive strategies.

In June 2025, the European Commission launched its Water Resilience Strategy (WRS), aiming for a water-resilient EU by 2050. With 30% of Europeans affected by water stress annually, the WRS addresses rising abstraction and degradation, calling for scaled-up investment in NBS within infrastructure.

One major UK initiative aligned with this vision is AWS’s reservoir plan, delivered by AtkinsRéalis, Mace Group and Turner & Townsend. Declared nationally significant, it will supply 200 million litres of drinking water daily to 750,000 homes, while also enhancing biodiversity and climate resilience through wildlife habitats.

AWS, among many other companies, are working to address the combined sewer overflow (CSO) crisis via NBS. CSOs, designed to relieve excess water, now spill more frequently due to urbanisation, population growth and extreme rainfall – releasing pollutants that harm aquatic life.

To mitigate this, sustainable drainage solutions (SuDS) – a subset of NBS – are being deployed. Treatment wetlands and rain gardens filter pollutants, swales slow stormwater and green roofs add green space. Research suggests that NBS could reduce CSO spill duration by 30-60% and spill volume by 45-80%.

A compelling example is Maid Marian Way in Nottingham, where traffic redevelopment integrated SuDS—tree pits, permeable paving, swales and rain gardens—to ease sewer pressure and boost climate resilience. These interventions show how NBS can transform urban infrastructure while protecting ecosystems.

NBS in Wales: landscape-scale impact

In Wales, NBS are central to sustainable land management and landscape-scale innovation; collaborations are driving transformative change across ecosystems and communities. Efforts in designated landscapes include restoring peatlands, woodlands and coastal habitats; improving freshwater health; and enhancing green infrastructure in towns and villages.

The National Landscapes Association NBS team is developing a pipeline of investible projects aiming to unlock green finance while keeping people and nature at the core. Tirweddau Cymru, a partnership of the three national parks and five national landscapes in Wales works closely with the Welsh Government to unlock funding such as the Sustainable Landscapes, Sustainable Places programme to deliver on nature recovery, decarbonisation and community resilience, and the newly launched Ffermio Bro programme which provides advice and capital funding to farmers and landowners for environmental improvements. It also fosters collaborative, landscape-scale interventions that boost biodiversity, build climate resilience and secure the future of Welsh farming communities.

Looking ahead: scaling up nature-based resilience

It is clear that NbS are essential for not only slowing the deteriorating climate and biodiversity that the vast majority of the world’s population and its leaders, are helplessly watching spin out of control, but they are also important for reversing the damage that has been done. With enough effort and investment, ecosystems can begin to prosper and the climate begin to heal. Inroads are being made in developing large-scale NbS, but we must use this momentum to enact it on greater scales.

Further, leaders, businesses and societies need to be held accountable for inaction; promising to deliver and actually delivering are two different things. Through collaboration, innovation and hard work, we can take on the biggest challenges that humanity, and the environment, will face.

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Articles in the 'Tackling the twin biodiversity and climate crises' series:

• Announcing a CIWEM-CIEEM joint article series
• BNG and nature recovery

Read the latest CIWEM news articles, and learn more about CIEEM. You can explore the CIWEM Early Careers Network, and get involved with our Early Careers LinkedIn Group.

Isaac Bates is an assistant wastewater modeller at AtkinsRéalis
Sara Wynne-Pari is an nature recovery 30by30 advisor at Tirweddau Cymru
Tsz Kai Charles Lam is a senior sustainable development officer at Swire Properties