Have you ever thought about if the air you inhale is healthy? With the constant emission of gases and fossil fuels, it is nearly impossible to vouch for the purity of the air we breath in. So, how do we achieve zero emissions?

‘Net zero’ refers to achieving an overall balance between emissions produced and emissions taken out of the atmosphere. Like a bath with the taps on, an approach to achieving this balance can either be to turn down the taps (the emissions) or to drain an equal amount down the plug (removals of emissions from the atmosphere, including storage for the emissions such as ‘carbon sinks’).

In contrast to a gross-zero target, which would reduce emissions from all sources uniformly to zero, a net-zero emissions target is more realistic because it allows for some residual emissions.

This takes into account that some emissions are produced by ‘hard-to-treat’ sectors, such as aviation and manufacturing, where reducing emissions is either too expensive, technologically too complex or simply not possible.

In a net-zero scenario the residual emissions from these sectors are allowed as long as they are offset by removing emissions using natural or engineered sinks – gross negative emissions.

Negative emissions can be achieved in a variety of ways, by utilising nature or engineering. Most straightforwardly, this can involve planting more trees to absorb the CO2 in the atmosphere through photosynthesis – afforestation (planting new forests) and reforestation.

There are also negative emission technologies: some of the most commonly used involve carbon capture and storage (CCS). This works by capturing CO2 before it is released into the atmosphere, by removing carbon from the gases produced by burning fossil fuels, or using hydrogen or oxygen in the process. Once the CO2 has been captured, it is compressed into liquid state and transported so that it can then be pumped underground, usually at depths of 1km or more, to be stored into depleted oil and gas reservoirs, coalbeds or deep saline aquifers. The technology can capture up to 90% of CO2 released by burning fossil fuels in electricity generation and industrial processes such as cement production.

Combining these approaches, Bioenergy with Carbon Capture and Storage (BECCS is the process of growing plants, crops or trees, harvesting them for energy generation and then capturing the carbon given off so it can be stored underground.

We definitely stand a chance of getting the work done.

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