Reducing global warming: Low cost ways

Not only do we have the tools to slash emissions and curb global warming by 2030, but half of available carbon-cutting options are cost-free or very cheap, UN climate experts say.

Wind and solar

In 2019, total emissions were 59 billion tonnes, or gigatonnes, of CO2 or its equivalent in other greenhouse gases. The range of options identified by UN's Intergovernmental Panel on Climate Change (IPCC) would enable a reduction in emissions of 31 to 44 gigatonnes by 2030. There are four key areas where the total potential for carbon reduction is highest between now and the end of the decade -- solar and wind energy, reductions in deforestation, and restoration of forests and other ecosystems. Of those, solar and wind are also among the cheapest options available thanks to the steep drop in the unit costs of these technologies -- down 85 and 55 percent respectively between 2010 and 2019, according to the report. More investment in solar could see an emissions reduction of between two and seven gigatonnes of CO2 equivalent by 2030. Wind energy could save between 2.1 and 5.6 gigatonnes. Most of that potential, according to the report, would have essentially negative lifetime costs because they are cheaper than fossil fuel alternatives. Other energy generation options have a lower overall potential, with a higher cost, such as nuclear power and hydroelectricity.

Food and forests

Protecting and restoring natural habitats is the second most significant area for reducing CO2 emissions. Forests are crucial for absorbing CO2 generated by human activities, and the IPCC found that limiting deforestation and the destruction of grasslands could reduce net emissions between three and almost eight gigatonnes, largely at a low cost. Restoring these types of ecosystems would save one to five gigatonnes. But action in this category would be at the more expensive end of the range considered by the IPCC. Shifting to "sustainable" diets and reducing waste food could save more than two gigatonnes, the IPCC said, but it did not give a cost estimate because of wide global variability and a lack of data.

Transport and constructions

Electric vehicles (EVs) are the fastest-growing part of the automobile industry and if these cars and trucks are charged with low-carbon electricity they can significantly reduce emissions. Changes how we travel -- switching to public transport and bicycles – can also help. Electrification of global shipping and aviation sectors are also possible. Most industrial processes in general can be decarbonised through a combination of technology using electricity and hydrogen, carbon capture and innovation in the circular use of materials (i.e. recycling and reusing). It is possible to make existing and new buildings in all parts of the world either nearly zero-energy or low-energy. The construction of new highly energy efficient buildings have the greatest potential (between less than one and more than two gigatonnes), although costs are towards the higher end. In industry, meanwhile, most of the options -- beyond improving energy efficiency and cutting other greenhouse gas emissions -- are associated with higher costs. But the sector still has significant potential for reducing emissions, in particular the switch to less carbon-intensive energy sources.