Without appropriate intervention on universal access to safe drinking water, sanitation and adequate hygiene (WASH) services, the number of malaria and dengue cases in Nepal could increase by up to 27 percent and 44 percent, respectively, over 2011–2040, according to the new study of the Asian Development Bank (ADB) released on Thursday.

The report recommended that Developing Asia be made more committed to tackling climate change.

Based on a 2023 study supported by the ADB, over 2041–2070, case numbers could rise by as much as 69 percent for malaria and 113 percent for dengue.

However, the study said better access to drinking (tap) water and improved household waste management can reduce disease risks by eliminating informal water storage that serves as mosquito breeding sites.

The study also showed that Nepal’s investments to reach the Sustainable Development Goals on water and sanitation and improving waste management could reduce infections from malaria by 17 percent and from dengue by 41 percent in urban areas.

“Improving WASH services can also deliver other health benefits, such as lessening diarrhoeal disease and increasing good hygiene practices, as well as helping to build resilience to vector-borne diseases.”

The ADB research finds the impacts of climate change could reduce gross domestic product (GDP) in developing Asia and the Pacific by 17 percent by 2070 under a high-end greenhouse gas emissions scenario, rising to 41 percent by 2100.

Rising sea levels and falling labour productivity would cause the most significant losses, with lower incomes and fragile economies hardest hit.

The new research in the inaugural issue of ADB’s Asia-Pacific Climate Report details a series of damaging impacts threatening the region.

The report said that if the climate crisis continues to accelerate, up to 300 million people in the region could be threatened by coastal inundation, and trillions of dollars of coastal assets could be damaged annually by 2070.

The Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change projects that the risk of vector-borne diseases (e.g., malaria and dengue) will increase if individual economies do not take climate change adaptation measures.

Due to increased temperatures and altered weather patterns, more localities will become suitable breeding grounds for disease vectors, such as mosquitoes.

“Climate change has supercharged the devastation from tropical storms, heat waves, and floods in the region, contributing to unprecedented economic challenges and human suffering,” said ADB President Masatsugu Asakawa. “Urgent, well-coordinated climate action that addresses these impacts is needed before it is too late.”

The report finds that regional public sentiment supports climate action. In an ADB climate change perception study this year, 91 percent of respondents across 14 regional economies said they view global warming as a serious problem, with many seeking more ambitious government action.

To address growing climate risks, adaptation responses need to be accelerated, and adaptation-focused climate finance must be greatly upscaled.

The report values annual investment needs for regional countries to adapt to global warming at between $102 billion and $431 billion—far exceeding the $34 billion of tracked adaptation finance in the region in 2021–2022.

On the mitigation front, the report shows that the region is well placed to embrace renewable energy and drive a transition to net zero and that forging ahead with domestic and international carbon markets can help achieve climate action goals cost-effectively.

Investments in WASH can help reduce health risks exacerbated by climate change.

The report said that agriculture is vulnerable to increased frequency of extreme climatic events due to climate change. However, achieving goals under the Paris Agreement on Climate Change is likely to depend on expanding carbon sequestration through forests, limiting land availability for agriculture.

In most Paris Agreement-compatible emissions pathways scenarios, bioenergy use rises, often combined with carbon capture and storage. Bioenergy production also reduces the land area available for growing food crops.

The report said that in 2023, the ADB released a study that models a set of scenarios compatible with the Paris Agreement, then contrasts these scenarios with current policies. This modelling considers both the deployment of bioenergy and expanded forest cover and other energy-related mitigation options.

The Paris Agreement compatible scenarios find that the land area for growing food crops in developing Asia will decrease by 36 million hectares by 2050 and 58 million hectares by 2070. Much of this is driven by the expansion of bioenergy crops, which will reach 97 million hectares in the region by 2070. As a result, food prices will reach values 35 percent higher than they would be under current policies by 2065.

“Agriculture, therefore, clearly needs adaptation to emissions mitigation policies, as well as to the impacts of climate change, to avoid adverse food security outcomes,” the report said.

Climate change will lead to new disease burdens, including new and emerging climate-related vector-borne diseases (e.g., chikungunya, dengue). The G20 High-Level Independent Panel calls for more robust disease surveillance and detection networks, coordinated regional action and information sharing.

This will require a significant expansion of surveillance networks and the development of global, regional, and national expertise.

Embodied agricultural innovations, including stress-tolerant varieties, can help address climate shifts using existing extension systems. Agricultural research has a key role in adaptation, and related studies provide very positive cost-benefit ratios for investing in research to address climate change risks.

High-returns research products include stress-tolerant crop varieties, especially for drought and floods.

They require transmission of much more information among farmers. More iterative and interactive extension approaches, such as farmer field schools, demand responsive approaches, such as farmer contracted extension, and gender-sensitive approaches all show promise to improve the adoption of knowledge-intensive practices, according to the report.

As climate change may affect the energy sector, the report said there is potential to build climate resilience into energy supply. The Asia and Pacific region is receiving some of the most significant flows of investment into energy supply, with an increasing share of this investment being in green and renewable energy.

However, this new infrastructure is vulnerable to climate change, especially given its long lifetime, and it is important to address these climate risks during design, a concept known as ‘climate-proofing’.

“Doing so involves low additional costs and is highly cost-effective, generating benefits four times greater than the costs,” the report said.

Several smaller economies, including Bhutan, Nepal, the Kyrgyz Republic, and Tajikistan, generate most of their electricity (86 percent-100 percent) through hydropower.

According to the report, substantial investments are needed in generation capacity and energy storage, grid enhancement, and smart grid technologies to manage the intermittent nature of sources such as wind and solar energy and achieve net zero emissions.

Meanwhile, the extensive hydropower resources in developing Asia can support grid stability as wind and solar power capacity increases, and enhanced grid interconnection can help mitigate intermittency challenges further.

However, effective climate-proofing often requires enabling actions by the government, including changes to design standards.

Nepal’s second Nationally Determined Contribution, or NDC, is each country's national climate action plan under the Paris Agreement. The submission provides more details than the first plan. It includes quantified targets for agriculture, energy, forestry, and waste and a commitment to gender equality and social inclusion by empowering women, Indigenous people, and youth in climate policy.

Despite these updates, the report said that NDC commitments across developing Asia remain insufficient to align with the Paris Agreement goals.

The report said that 44 economies of developing Asia with submitted NDCs all include targets for the energy sector. Still, only 40 include targets for the agriculture, forestry, and other land use sectors.

Moreover, just 30 economies have targets for the industry sector despite this sector's crucial role in decarbonisation.

Forty- four economies, representing 98 percent of the region’s emissions, have ratified the 2015 Paris Agreement and submitted nationally determined contributions (NDCs) with commitments to cut GHG emissions and adapt to climate change.

In addition, 36 of these economies have announced or adopted net-zero targets. However, according to the report, current actions fall short of what is needed to limit the global temperature rise to 2°C or, ideally, 1.5°C.

The NDCs and net zero targets lack concrete, sector-specific emission reduction road maps.

Implementing decarbonisation plans faces key challenges, including institutional capacity gaps, governance issues, insufficient financing, limited access to technology and expertise, and vulnerability to climate events that divert resources from decarbonisation efforts.

The ADB climate change perception survey conducted in 2024 finds that 91 percent of people in 14 economies in developing Asia view climate change as a severe problem. Additionally, 84 percent of respondents report that they and their families are already experiencing climate change impacts or expect to within the next decade.