Think “climate change" and “carbon dioxide" is probably one of the first things that comes to mind. “Copenhagen", symbolizing all of the tension and nuance of international action, is probably a close second. “Catastrophe" might be another association, as reports about glacial melting, monsoon disruption, sea levels rising and other environmental changes pile up.

But the truth is that the CO2 emissions at the centre of international discussions only account for half of global warming to date. Half is big and CO2 should be at the centre of the debate, especially since what we emit today will contribute to warming for centuries. But it’s still just one half. The other half offers precious opportunities to tackle climate change and see the positive effects quickly while at the same time meeting development goals.

Illustration: Jayachandran / Mint

The other half of global warming offers several possibilities for rapid impact. Ground-level ozone, produced as emissions from transport, biomass burning and other sources, has a warming effect about 20% as great as CO2, but it only lasts in the atmosphere for weeks to months. Stop the production of ozone, and the concentration (and the warming effect) drops quickly. Methane, released from agriculture, cattle, gas leaks and wood burning, has about 30% of the warming impact that CO2 does. Today’s methane emissions will have mostly broken down into CO2 and water in a decade. Black carbon, dark particles in soot, smoke and the tailpipe emissions of many of the cars and buses around us, has as much as 55% the impact of CO2. It absorbs solar radiation and warms the air as well as whatever it happens to be sitting on—including glaciers and snowpack. Scientists estimate that black carbon contributes as much as carbon dioxide to the melting of India’s Himalayan glaciers. But it dissipates from the atmosphere within a few weeks—stop the emissions, and warming slows almost immediately.

The technologies to reduce black carbon, methane and ozone relatively cheaply already exist. The transport sector (particularly diesel engines) and households burning wood, crop waste, cow dung and other biomass are two major contributors to black carbon and ozone in India. Both could be cleaned up with existing commercially available technologies. Filters and particle traps can reduce black carbon emissions from trucks, cars and other diesel engines with minimal or no loss of fuel efficiency. Switching fuels and reducing adulteration also help reduce emissions. For instance, Delhi’s move from diesel to compressed natural gas for urban transport was estimated to reduce climate-forcing emissions by 10-30%. Catalytic converters, ubiquitous in newer vehicles, reduce emissions of some of ozone’s precursors. Commercially available stoves can reduce household black carbon, methane and ozone precursors, while solar cookers or biogas can reduce overall contribution to climate change to nearly zero. Methane emissions from landfills can be captured and even converted into electricity. Black carbon from coal-based power plants can be trapped at the smokestack; emissions from small industries such as traditional brick kilns can be readily reduced by moving to newer types in use and available in India.

The rewards for successfully deploying these technologies and practices go well beyond environmental sustainability. Reducing black carbon and ozone would be a public health victory. Black carbon from household emissions is one of the top contributors to respiratory illness and premature death in the developing world, especially among women and children. Some estimates show that Indians lose as many as two billion workdays due to indoor air pollution-related illness and this does not include the uncounted lost schooldays. Ozone and black carbon also contribute to respiratory illness as part of urban air pollution. Lowering these two pollutants would also boost agricultural productivity. Black carbon and the other substances emitted with it from fossil fuel and biomass burning affect rainfall patterns and solar radiation available for plants. Ozone affects photosynthesis and damages plant cells even far away from urban centres. It can lead to double-digit reductions in yields for staple crops including wheat, something that India can ill afford.

Tackling the other half of global warming is far from easy, but many of the obstacles are familiar challenges already on the list as development priorities. Disseminating cleaner burning stoves and ensuring fuel supply networks, for example, is not so different from disseminating water filters or vaccines. Any innovations in business models, subsidy programmes and design techniques that succeed in making more efficient stoves affordable, available and desirable as appliances would offer lessons for other technology dissemination programmes. Encouraging small businesses to adopt cleaner technologies involves both improving regulatory enforcement capacity and opening up access to finance—both steps that contribute to development goals beyond emissions reduction. Successful models for financing brick kiln upgrades or shifting to efficient commercial stoves, for example, could pave the way for more general expansion of financial options for small businesses. Implementing methane capture at landfills requires the same kinds of infrastructure project structuring —and the same kind of effort to actually create the landfill and get the trash into it—that any urban waste management initiative struggles with.

The other half of global warming has not yet captured the public eye. But once it is on the radar screen, the opportunities are hard to ignore.

Jessica Seddon Wallack is director, Centre for Development Finance at the Institute for Financial Management and Research, Chennai. Comments are welcome at