Climate change is one of the primary drivers of biodiversity loss. Changing temperatures affect marine, terrestrial, and freshwater ecosystems around the world, resulting in the loss of local species and the mass mortality of plants and animals. The IPCC has warned that the risks of species extinction increase with every degree of warming, and we know that surpassing 1.5°C of warming will result in the total collapse of certain ecosystems – for example, a 70% to 90% reduction in global coral reefs. Over 3°C of warming is expected to result in the loss of one quarter to one half of terrestrial species. As the abundance of biodiversity is reduced, so is its functionality, as forests, wetlands, and other carbon sinks have a reduced capacity to absorb emissions.
At the same time, pollution deeply impacts nature. Harmful air pollutants like nitrous oxides and sulfur dioxides from fertilizers, fuel combustion, and other sources seep into ecosystems through water, soil, and vegetation. This stunts vital processes such as carbon and nutrient cycling, and results in the acidification and eutrophication of water systems causing acid rain, algae blooms, a loss of oxygen and aquatic life, and the pollution of potable water sources. Nitrogen oxides along with methane are also precursors to tropospheric ozone, a harmful air pollutant and climate forcer which impedes plant growth and seed production. Staple agricultural crops, grassland species, and tree species are all impacted, resulting in the loss of 25 million tonnes of crops a year, and increased land use for agriculture resulting in the further loss of habitat.
Air pollution and climate change are not separate crises. Many air pollutants are also climate forcers, and many greenhouse gases are emitted from the same sources as harmful pollutants, impacting ecosystems and biodiversity on a global scale.
What we're doing
Since 2012, the CCAC has taken an integrated approach to tackling climate change and air pollution through the reduction of short-lived climate pollutants (SLCPs), resulting in co-benefits for people and planet. SLCPs are air pollutants as well as climate forcers, meaning they can be targeted simultaneously.
Responsible for 45% of current warming, reducing SLCPs is one of the most effective options for slowing the rate of global warming in the near term, avoiding critical tipping points of species extinction. As a 2018 IPCC report indicated, “modelled pathways that limit global warning to 1.5°C with no or limited overshoot involve deep reductions in emissions of methane and black carbon.” With an estimated 5% of all species threatened with extinction by 2°C of warming above pre-industrial levels, SLCP reductions are vital for the preservation of biodiversity. According to the CCAC-UNEP Global Methane Assessment, reducing methane alone by 45 percent would just avoid nearly 0.3°C of global warming by 2045 and keep the Paris Agreement within reach.
While achieving climate benefits, the CCAC works across the fossil fuel, agriculture, waste, and transportation sectors to reduce SLCPs that negatively impact ecosystems. The majority of SLCP mitigation measures proposed are nature-positive – and come at low or no-cost.
Because the fossil fuel sector is responsible for 35% of human-caused methane emissions, it’s critical to prevent the formation of tropospheric ozone from fossil fuel production and consumption including power plants and oil refineries. Measures to reduce methane include reducing leakages from long-distance gas transmission and distribution pipelines, extending recovery and utilization from gas and oil production, recovering and using gas and fugitive emissions during oil and natural gas production, and pre-mining degasification and recovery and oxidation of methane from ventilation air from coal mines.
Low-cost measures in the agriculture sector can reduce methane emissions, tropospheric ozone, and ammonia, which is a main source of nitrogen pollution with a major effect on biodiversity. These activities include improved manure management and animal feed quality, intermittent aeration of continuously flooded rice paddies, improved animal health and husbandry, promoting farm-scale anaerobic digestion, and fertilizer alternatives. Since 2012, the CCAC has supported agriculture activities in over 20 countries, including introducing actions to reduce methane emissions from manure in China’s 14th Five-Year Plan.
Measures to reduce methane from waste include separating and treating biodegradable municipal waste and turning it into compost or bioenergy, upgrading wastewater treatment with gas recovery and overflow control, improving anaerobic digestion of solid and liquid waste in the food industry, upgrading primary waste-water treatment, diverting organic waste, and collecting, capturing, and using landfill gas. At the same time, waste incineration can be a source of harmful nitrous oxide emissions, minimized by reduced open burning.
Nitrogen oxide emissions from diesel cars, trucks, and buses are a major contributor to air pollution-related deaths worldwide—and the impacts are increasing, despite regulatory limits. Nitrous oxides and sulfur dioxides are reduced by introducing low-sulfur fuels and soot-free diesel engines in heavy-duty vehicles, enforced with national and regional fuel standards. Nitrous oxide is also a potent greenhouse gas, with a climate warming Since 2020, the CCAC has supported over 60 countries in advancing these measures and engaged with 28 major cities worldwide.
To learn more about the activities funded through the CCAC Trust Fund, click here.