What is Black Carbon?

Black carbon is a type of particulate matter, or “soot.” It’s the main component of diesel exhaust and is also emitted from power plants, forest fires and residential wood burning.

What is Global Warming?

Global warming is the long-term rise in the average temperature of the Earth’s climate system. It is a major aspect of current climate change and has been demonstrated by direct temperature measurements and by measurements of various effects of warming. The term commonly refers to surface temperature increases but includes global warming caused by increased emission of greenhouse gases from human activity.

There is a scientific consensus that human-caused global warming is occurring. The Intergovernmental Panel on Climate Change (IPCC), a group of 1,300 independent scientific experts from countries all over the world under the auspices of the United Nations, has stated that there is “unequivocal” evidence that the Earth’s average surface temperature has increased by 0.6 °C (1.0 °F) since pre-industrial times, and will likely increase by a further 1.5–2.0 °C (2.7–3.6 °F), depending on future emissions and on natural variability.

The scientific consensus is that this warming trend is largely caused by increased emissions of greenhouse gases, such as carbon dioxide and methane, produced by human activity.

These higher temperatures are causing many physical and chemical changes to the Earth system, including rising sea levels due to thermal expansion of the ocean and melting of ice sheets and glaciers; more frequent extreme weather events such as heatwaves, droughts, and heavy rains; ocean acidification as CO₂ dissolves in seawater; and species extinctions as changing conditions force animals to find new habitats or face starvation.

The United Nations’ Intergovernmental Panel on Climate Change has issued five comprehensive assessment reports that document the scientific consensus on climate change, and its physical and socio-economic impacts. The most recent ( Fifth Assessment Report, AR5) was published in 2014.

Impact of Black Carbon on Global Warming

When black carbon particles are released into the atmosphere, they absorb sunlight and heat up the surrounding air. They also contribute to the formation of ground-level ozone, which is a main component of smog.

Black carbon has a short atmospheric lifetime of only a few days to weeks. But it’s an extremely potent climate pollutant, second only to carbon dioxide in terms of its contribution to global warming.

Black carbon is a major contributor to global warming, accounting for about 18% of all human-caused greenhouse gas emissions. When emitted into the atmosphere, black carbon absorbs heat and warms the planet. The main sources of black carbon emissions are the combustion of fossil fuels, biofuels, and biomass burning.

In the past decade, there has been a growing body of evidence linking black carbon emissions to climate change. For example, a 2006 study found that black carbon was the second most important human-caused contributor to global warming after carbon dioxide (CO2). A 2013 study estimated that black carbon emissions from all sources account for about 0.5 degrees Celsius of global warming.

The good news is that black carbon’s short lifetime in the atmosphere means that reducing emissions can have an immediate impact on climate change. In fact, a recent study found that reducing black carbon emissions could slow the rate of global warming by up to 0.6 degrees Celsius by 2050.