Human emissions of greenhouse gases are the primary drivers of climate change . But where do these emissions come from?
Where do emissions come from?
Where do greenhouse gas emissions come from?
There are two popular ways to categorize greenhouse gas emissions from human activities :
By source - where the overall emissions are produced
By end use - within each source what the emissions are used for
This chapter will look at the source of emissions. The next will explore which end products are most responsible. All of the data on both of these methods for measuring emissions can be summarised in one amazing chart:
World greenhouse gas emissions split into sector and end use
The left side of this chart splits emissions into which sector they come from, e.g. energy, agriculture and waste. The right column of the chart shows emissions by end-use activities. This helps us understand the emissions released in the making of specific products and activities.
Which sector produces the most emissions?
The production and distribution of energy produces 76% of greenhouse gas emissions!
Percentages of world greenhouse gas emissions split into sector
This includes emissions from producing heat and electricity, transport fuels, buildings, gas leaks and energy for producing fertilizer and consumer goods .
Sources of greenhouse gas emissions from the energy sector
Without including emissions from energy use, farming and land use change accounts for 14.8% of emissions (if we include emissions from energy use, this number is even higher!). This makes farming and land use change the next biggest source of greenhouse gas emissions after energy .
Actually all of these processes release greenhouse gases into the atmosphere!
Sources of greenhouse gas emissions from the agriculture sector
This sector also includes emissions from land use changes. Trees and healthy soils tend to absorb more CO₂ from the atmosphere than they release . They are what’s known as carbon sinks. But when forests are cleared for farms, roads and buildings, the carbon that is stored in them is released back into the atmosphere .
Trees remove carbon from the atmosphere
The next sector after agriculture is industry, which accounts for 5.9% of emissions. This includes emissions from producing cement, chemicals, and various other materials (like plastics, rubber and man-made fabric).
This is one of the fastest growing sources of greenhouse emissions and has grown by 174% since 1990! .
Earthly making cement
Waste in landfills, sorting wastewater and treating human sewage all produce greenhouse gases, especially methane and nitrous oxide . The largest source of these comes from landfilling of solid waste, including food waste.
Emissions from waste
So, we’ve seen which sectors release the most greenhouse gases. Now let’s look at which end uses/activities are responsible for these emissions.
. But where do these emissions come from?
