About greenhouse gases, politicians and activists

They travel in droves to places like Dubai, politicians and climate activists. They are to decide when fossil energy will run out in order to save the climate, but no one is talking about the problem, which is perhaps a little more complex than which fuel is used in the means of transport. Cars, lead and boats.

Population growth no one wants to talk about

It is clear that population growth plays a significant role in the increase in man-made emissions of greenhouse gases, in Norway and in the rest of the world1. In Norway, immigration has increased the population by approx. 20% in a few years, and the emissions from Norway have necessarily increased accordingly if the argument is that humans create emissions of CO₂ something few dispute.

A simple model that shows the connection between emissions and population growth is the following:

ΔE=ΔP×PE ×EC ×CB

 

Here is:

• $\Delta E$ is the change in emissions.
• $\Delta P$ is the change in population.
• $E$ is the energy consumption.
• $P$ is the population.
• $C$ is the carbon intensity.
• $B$ is GDP per capita.

The model shows that emissions are proportional to population growth, but also to economic growth, technological level and behavioral patterns. If we want to reduce emissions, we must therefore influence one or more of these factors. The solution may be difficult to find when no one is talking about one of the most important factors, population growth.

A study that uses this model on data from 11 selected countries and the world as a whole shows that population growth contributes to increasing emissions by between 0,5 and 1,5 per cent per year in the period 2005-2019. This is lower than economic growth, which contributes between 1,5 and 3,5 per cent per year, but higher than technological improvement and behavioral change, which contributes between -0,5 and -2,5 per cent per year[1].

Another study that looks at the relationship between population growth and the CO2 concentration in the atmosphere for the period 1963-2019, finds a perfect relationship between these two variables[2]. This study assumes that the CO2 concentration is proportional to population growth, and that the other factors are constant.

However, this assumption is not realistic, because the other factors vary over time and between countries. For example, China and India have experienced rapid economic growth, while Norway and Sweden have experienced a high degree of technological improvement and behavioral change. Therefore, it is more nuanced to use the first model, which takes all factors into account.

The conclusion is that population growth is an important, but not the only, reason for increased CO2 levels in the atmosphere. If we want to reach the Paris Agreement and limit global warming to below 2 degrees Celsius, we must reduce emissions from all sources, including population growth. This will require a combination of political measures, technological solutions and behavioral changes.

Which politician or environmental activist would then propose to do something about population growth? If you don't understand the problem, how can you solve a problem?

1. Greenhouse gas emissions: The role of population growth must be discussed - Energy and Climate
2. How much of climate change can be explained by increased population growth? (forskersonen.no)