Renewable energy and energy efficiency

The figure below shows the total global anthropogenic greenhouse gas emissions in carbon dioxide equivalent CO2e, broken down by greenhouse gas and economic sector.

Total global anthropogenic greenhouse gas emissions in carbon dioxide equivalent CO2e by greenhouse gas and, within this, by economic sector. LULUCF stands for Land Use, Land-Use Change and Forestry. Source

The relationship between the sources of greenhouse gas emissions, the sectors responsible for them and the radiative impact of different greenhouse gases is shown in the next illustration. It can be seen that greenhouse gas emissions affect many sectors of the economy and the processes associated with their activities.

Global greenhouse gas emissions in 2012 by emission source, economic sector and greenhouse gas…. Direct emissions (in addition to the burning of coal, gas and oil) are responsible for, among other things, deforestation, animal husbandry or landfill sites.


By far the largest source of greenhouse gas emissions is the burning of fossil fuels: coal, oil and gas, the backbone of the global energy system.

Global primary energy consumption from 1850 to 2017 by energy source. Source – Etemad B., Luciani J., World energy production 1800-1985, Librairie Droz, 1991; BP Statistical Review of World Energy 2018; Electricity conversion rate 12 TWh = 1 mtoe.

The growing trend in energy consumption shows the scale of the challenge. Reducing emissions to a level to meet the target agreed by the world’s nations under the 2015 Paris Agreement – limiting the average global temperature increase to a maximum of 2°C means that CO2 emissions to the atmosphere must be completely phased out by 2050, which, in the absence of the availability of CO capture technologies,2 is virtually the same as having to stop burning coal, oil and gas by 2050.

This is a huge challenge.

Not only will it be necessary to radically expand zero-carbon energy sources from their current low levels: wind, solar and nuclear power together provided only 2.2% of total primary energy globally in 2017, hydropower approx. 2.5%, and biomass around 10% (with the majority being wood and excrement burned primitively in poor countries).

It will also be absolutely fundamental to improve energy efficiency, from construction to transport, industry to agriculture and other sectors of the economy, so as to provide a good level of energy services based on the most efficient use of energy.

There is no doubt that replacing fossil fuels with renewable energy (RES) will not be easy. However, the aforementioned energy efficiency comes to the rescue. By improving the thermal conditions of our flats and houses, we achieve a much lower energy demand and thus less ‘fuel’ has to be used to heat our household. Nowadays, we already have quite a few possible solutions: biomass, wind energy, solar energy (in various variants), water, a variety of waste and many others. It is high time to reach for them in a smart way. (Source: Marcin Popkiewicz “The energy revolution: but what for?”)

This article was written with the consultation of CLIMATE SCIENCE.