To stop climate change, we need the global emissions to be zero
! If we could bring P, C, or E down to zero, then we would have no emissions – it’s basic maths: multiply anything by zero and you’ll get zero. Let’s explore the three options!
How will the global population (P) change?
12 thousand years ago, there were 4 million people on the planet – nowadays, there are twice as many people living just in London!
About 2 hundred years ago the global population started to grow very rapidly. There are now about 7.7 billion of us and it’s predicted that we will reach about 9.7 billion by 2050.
From this graph you can see how fast the population is growing, and that it will start to plateau in the future around 2100:
To get emissions down to zero, we clearly can’t have zero people! So, let’s look at the next option.
How has consumption (C) changed?
Energy use per person increased by 44% between 1971 and 2015 and people are eating more food (especially meat). In general, it is clear that resource use per person has been increasing rapidly.
The Gross Domestic Product (GDP) is a measure of the total financial value of finished products and services produced in a country in a specific time period. The global GDP is the sum of GDPs from all countries and can be used to estimate total consumption.
GDP can be standardized to account for inflation and the currencies of different countries. Global standardized GDP per person increased by 140% between 1970 and 2016:
Should we decrease consumption (C)?
Today, there are around 1.3 billion people living in poverty. In order to give these people better lives, they require things like access to clean drinking water, electricity, and medicines. Therefore, in less developed countries we want consumption to increase to help improve people’s quality of life.
But people in high-income countries can and should consume less. Each person can choose to (or be encouraged to) reduce their total consumption (i.e. decrease C). Perhaps even more importantly, people can shift to consuming products that cause lower emissions (i.e. products with lower E).
However, since we can’t stop consuming things completely, there’s only one component left to target to get emissions down to zero…
Getting emissions per service (E) to zero
Unlike population and consumption, the emissions released per service have been decreasing over the past decades. This graph shows the decrease since the 1950s in CO₂ emissions per standardized $GDP per person:
In other words, for every ‘thing’ that we consume, we cause less climate change than we did 50 years ago.
Engineers and scientists have created technologies that decrease the emissions from a lot of our consumption. Firstly, we can now generate energy in ways that produce far less greenhouse gas emissions. In 2018, just 8.5% of power came from low-emission sources like wind, solar and nuclear.
Moreover, we now have products and services that use less energy (e.g. light bulbs). Similarly, the average car in 1975 emitted about 422g of CO₂ for every kilometre it drove, whilst today, driving a kilometre emits only 217g of CO₂.
Zero-emission energy technologies such as renewables and advanced nuclear are the single most important priority right now. How successful we are depends on how much effort and investment we devote to improving and implementing sustainable technologies, and, also importantly, on what is physically possible!
Can we get E to zero for all products and services?
Unfortunately, no..
