Short-Lived Climate Pollutants

Short-lived climate pollutants are powerful climate forcers that remain in the atmosphere for a much shorter period of time than carbon dioxide, yet their potential to warm the atmosphere can be many times greater. Certain short-lived climate pollutants are also air pollutants that have harmful effects for people, ecosystems and agricultural productivity. 

The short-lived climate pollutants black carbon, methane, tropospheric ozone, and hydrofluorocarbons (HFCs) are the most important contributors to anthropogenic global warming after carbon dioxide, responsible for up to 45% of current global warming. If no action to reduce emissions of these pollutants is taken in the coming decades, they are expected to account for as much as half of warming caused by human activity. 

Why are short-lived climate pollutants important?

When people talk about reducing climate change, they often focus on carbon dioxide (CO₂) emissions, and for good reason. CO₂ is the primary driver of climate change. It remains in the atmosphere for hundreds of years, meaning that once in the atmosphere, it can continue to affect the climate over a long timeframe.

While decarbonising is essential to stopping climate change, mitigation efforts focused solely on CO₂ will not be enough to slow the warming trend - especially not in the near term.  

Because short-lived climate pollutants can be removed from the atmosphere in periods ranging from days to 15 years, reducing their emissions can make quick headway on slowing global warming. These pollutants can be significantly reduced using technologies available today, and actions to reduce them have the potential to deliver additional benefits for human health, crop yields, and economies. 

Speed is increasingly crucial in the fight against climate change. The planet has already warmed more than 1°C. According to the International Panel on Climate Change (IPCC),  warming above 1.5-2°C would have devastating consequences. The only way to avoid passing this threshold - and the most dangerous impacts of climate change - is by reducing short-lived climate pollutants hand-in-hand with deep and persistent cuts in carbon dioxide.

Reductions in the emissions of short-lived climate pollutants can lead to relatively rapid changes in atmospheric concentrations, with benefits materializing in a relatively short timeframe. 

Maximum possible reductions in short-lived climate pollutants – which can achieve a 0.6°C reduction in warming – must be combined with maximum possible CO₂ reductions to slow the rate of global warming and achieving the 1.5°C target set by the Paris Agreement. Such actions would also prevent climate tipping points that could exacerbate long-term climate impacts and make adapting to climate change harder, especially for the poor and most vulnerable. 

Human health impact

Every year, nearly 7 million people die prematurely from the effects of indoor and outdoor air pollution. Short-lived climate pollutants contribute significantly to this massive health impact. Fast action on key sources of short-lived climate pollutant emissions, such as the widespread adoption of clean cooking and heating technologies and fuels, has the potential to prevent around 2.4 million deaths each year, particularly among women and children. 

Agriculture impact

Feeding a growing world population is a major development challenge, and we cannot afford to lose millions of tonnes of crops each year to air pollution. 

Tropospheric ozone is responsible for staple crop yield losses of up to 12% for wheat, 16% for soybean, 4% for rice, and 5% for maize. Rapidly reducing precursors to ozone formation – of which methane comprises 50% – has the potential to avoid the annual loss of more than 50 million tons of crops per year. Such reductions can be achieved through already available actions in the agriculture, waste, and oil and gas sectors.  

The potential impact of rising oceans is one of the most concerning effects of climate change, as many of the world’s major cities, including Amsterdam, Bangkok, Calcutta, Dhaka, Miami, New York, Shanghai and Tokyo, are located in low-lying coastal areas.

If temperatures continue to rise, sea levels may increase by up to a metre this century. That increase could submerge densely populated coastal communities, especially in the event of storm surges, which are expected to become more frequent. 

Immediate implementation of short-lived climate pollutant control measures could reduce the rate of sea-level rise by about 20% in the first half of this century as compared to a reference scenario. By 2100, full mitigation of CO₂ and short-lived climate pollutants could reduce the rate of sea-level rise by up to 50%, which would give coastal communities and low-lying states time to adapt.