Greenhouse gas (GHG) emissions is the single-most important indicator when it comes to the impact of the human civilization on our climate. Thus, much energy has been given to measuring, accounting and maintaining an inventory of emissions from different entities, economic activities and even countries.

Measuring emissions can, however, take different forms. The simplest of them all is “absolute emissions”, which is simply the amount of GHGs from a particular entity or activity.

However, this is not the only way to measure and report emissions. Different units have emerged to bring nuance and context into emissions reporting, among which the most commonly used metric includes “emissions intensity”.

Emissions Intensity: Putting emissions into context

Those of you familiar with the Indian climate change developments must have come across India’s Nationally Determined Contributions (NDCs) — India’s stated commitments under the Paris Agreement. Among the NDCs is a prominent target that reads…”To reduce Emissions Intensity of its GDP by 45 percent by 2030, from 2005 levels” (source).

Other economic sectors also choose to use emissions intensity as a preferred unit of their climate impact – most notable the hard-to-abate sectors like steel and cement. For example, the steel sector under the World Steel Association targets a 58% emissions intensity reduction in crude steel production by 2050 compared to 2019 to align with sustainable development and climate goals (source).

Emissions intensity is subtle: it is the amount of emissions per unit of an activity or economic output.

In the case of how India has framed its NDC, a reduction in emissions intensity means that for every unit of GDP of the country, the resultant emissions decrease, signifying an improvement in the efficiency of operations of the country’s major industries.

From a narrative perspective, this is convenient – even if emissions increase overall, the emissions per unit of GDP could decrease if the GDP value rise. This is almost certainly going to happen with India and other developing countries that seeks to rapidly develop but does not have access to affordable low-carbon technologies at scale. Likewise, emissions from steel production are likely to remain significant unless drastic technological measures are embraced. It is also true, however, that the production of steel is going to increase manifold by 2050 to meet growing urban and industrial demands. Therefore, emissions are going to increase – but by improving the efficiency of operations, the emissions per unit of steel produced will decrease, thus reducing emissions intensity.

Is emissions intensity a bad metric to report progress in reducing emissions?

Emissions intensity as a unit can seem like it has been chosen to intentionally hide true climate impact. Measuring and trying to achieve a reduction in absolute emissions must be a long-term goal for any entity to seriously demonstrate climate leadership.

However, emissions intensity is a useful metric to set and achieve realistic short-term goals and is therefore, justified.

It provides a short-term target for countries and industries that have no viable options to reduce emissions in the short-term. Hard-to-abate sectors are notable examples, where the technology just doesn’t exist for them to not emit GHGs while producing their products. Do they just give up and wait till such a technology develops? The world (rather human civilization) does not have that kind of luxury. Instead, emissions intensity as a metric allows these industries to improve efficiency and make gains while the technology for low-carbon processes develop simultaneously.

The same logic applies for countries like India that needs to develop and bring millions out of poverty, and the entrenched economic system does not allow any drastic switches away from fossil fuels (unless you want a complete disaster in your hands). Emissions intensity is therefore, a worthwhile short-term target. Notably, India has committed to achieving net-zero by 2070 – which is a measure of absolute emissions and becomes a viable long-term target to achieve.

Avoiding the Jevon’s Paradox

Named after economist William Stanley Jevons, this paradox highlights that improvements in efficiency can sometimes reduce costs of that process, leading to much greater demand and therefore, overall resource use. For example, increased efficiency of fuel use in airplanes can reduce emissions from air travel. But increased fuel efficiency can also translate to cheaper flight tickets, making air travel more accessible and therefore, more flyers and flights. This would negate the emissions reduced from negates the efficiency gains.

This remains the biggest pitfall in relying too much on emissions intensity as a metric to measure progress against climate goals. India has taken a pragmatic and well-informed approach in not only setting short-term emissions intensity targets but also establishing a long-term absolute emissions target, which should avoid this paradox.

Next time you see any intensity based target (not just related to emissions), you now know how to interpret it. And don’t forget to question it from the lens of the Jevon’s Paradox!