Low carbon refers to products and activities that generate relatively low amounts of carbon dioxide over their entire life cycle, including construction, fuel supply, operation and eventual decommissioning.
Electricity generation and heating account for about 33 percent of global carbon dioxide emissions. Among energy sources, wind, nuclear, tidal, hydropower, geothermal, and solar power have the lowest life-cycle emissions. Onshore wind produces around 11 grams equivalent per kilowatt-hour produced, followed closely by nuclear at about 12 grams, hydropower at 24 grams, geothermal at 38 grams, and solar photovoltaic at 41 to 48 grams depending on the technology. In contrast, fossil fuels emit from 400 to more than 1000 grams per kilowatt-hour.
Transportation contributes about 16 percent of global carbon dioxide emissions. Walking and cycling produce nearly zero emissions. For powered intercity passenger transportation, rail is the lowest carbon mode, emitting about 80 to 97 percent less than automobiles or short-haul airplane flights.
For intercity freight transportation, the lowest carbon mode is generally rail, with emissions of about 25 percent those for road transport and only about 15 percent those for air transport. Inland barge freight transportation typically has even lower carbon emissions at about 28 percent less carbon dioxide per ton-mile than trains, although its use is limited by geography and slower speeds.
Zero carbon means producing no carbon dioxide emissions, whereas carbon neutral and net zero refer to offsetting any emissions by removing an equivalent amount of carbon dioxide from the atmosphere.
A low-carbon economy aims to minimize or halt climate change by minimizing carbon emissions from all sectors of the economy through the use of renewable energy, improving energy efficiency and adopting sustainable practices.