Transition to carbon-free society a matter of civilisation's survival

The mechanism that creates the green house effect comes from the correlation between carbon dioxide emissions and warming of the atmosphere. Solar energy is warming up the planet and a large part of this energy transforms into infra red or thermal radiation, which is leaving the planet.

A part of this infrared radiation is absorbed by the atmosphere and directed back to the surface, which is why the average temperature on the planet is around 20 degrees Celsius, and the differences between day and night temperatures are relatively small.

Carbon dioxide, water vapour, methane and other gases in the atmosphere strongly absorb infrared or thermal radiation. Water vapour absorbs most of it and CO2 is specific because it absorbs the radiation in the wave lengths where water vapour can no longer absorb it.

Consequently, more thermal radiation returns to the ground because the atmosphere acts as a better thermal insulator due to the higher carbon dioxide concentrations.

Climate models to help make reliable future scenarios

Research has shown that in the last 2,000 years the global temperature of the Earth's surface was relatively stable until approximately the 16th century. Then it starts to drop. This is why at the beginning of last century, experts believed a new ice age was coming. But measurements collected since 1850 show that in the last 200 years the cooling trend has not only stopped but has drastically reversed.

Martin Čopič, professor emeritus at the Faculty for Mathematics and Physics at the University of Ljubljana, has no doubts that there is a direct connection between this temperature rise and the increased amount of carbon dioxide in the atmosphere.

He has said at public lectures organised by the university that he had no doubt that humanity is responsible for the rise of CO2 in the atmosphere, as the increase started in the last 150 years of intensive industrial development. But despite the fact that scientists have known this for 40 years, in the last 30 years emissions have been higher than ever.

Today, researchers use climate models as a tool for more detailed analyses of the effect of the CO2 on the climate. These complex mathematical calculations assume scenarios of CO2 concentration trends and try to take into account known factors such as the sea, clouds and different land surfaces in as much detail as possible.

Five standardised scenarios used in climate models envisage different CO2 concentration trends in the coming decades. Under the most optimistic scenario (SSP1), CO2 emissions would be fully eliminated by 2050, which would lead to the global temperature rise by 1.6 degrees Celsius in the mid-term, which would be still acceptable, and a small drop in temperature by 2100.

The most pessimistic scenario (SSP5) envisages emissions rising in line with current trends. This would lead to a temperature rise of 2.4 degrees Celsius in the mid-term, at around 2060. By 2100 the temperature would be up by 4.4 degrees Celsius, which would pose a serious threat to human life on the planet.

Even under the medium scenario, which assumes that emissions start to decline in 2050 and temperatures rise by 2 degrees Celsius in the medium term, the consequences for everyday life would be severe. Extreme heatwaves would be common, there would be severe droughts in some places, severe flooding in others, and some parts of the planet may become completely uninhabitable. Sea levels would rise and ocean acidity would increase as ice melts at the poles, leading to the extinction of many species.

Changes in the atmosphere lead to changes in society

Čopič believes social consequences are inevitable too. "Deteriorating living conditions in certain parts of the world can lead to displacement on a scale never seen before in history. By 2100, between one and four billion people could find themselves in uninhabitable areas, depending on the scenario. This could lead to an increase in conflict and, unfortunately, ultimately to an increase in the risk of the use of nuclear weapons," he warns.

This is why he is convinced that it is crucial to use all currently available clean and renewable primary energy sources to achieve zero CO2 emissions. These energy sources include solar and wind energy, while the energy of water is for the most part already being fully exploited, and the world will probably not be able to resist the use of nuclear energy despite the reservations that a part of the public has towards it.

Geothermal energy also has relatively limited applications, and biofuels and natural gas exploitation will need to operate in a carbon-neutral way and in conjunction with CO2 capture and storage technologies.

Increasing clean and renewable primary energy sources must come at the cost of completely phasing out the use of fossil fuels such as coal and oil. Electrification is key in this respect and in all areas where it is possible.

Possible targets for electrification include cars and public transport and heat pumps for heating buildings and for industrial processes. Research has shown that such measures can reduce global primary energy use by almost a third, even at the same end-use. However, the world would probably need to generate more electricity than we do now to make such a transition successful.

We should also bear in mind that certain processes and activities cannot be electrified. Industrial processes such as steel and cement production, aviation and shipping, and heavy freight transport in general, also produce significant emissions.

Solutions are within reach but require a lot of effort and cooperation

Some of these problems can be solved by using hydrogen, synthetic methane and other liquid synthetic fuels, which are produced using primary electricity. Synthetic fuel production also requires CO2 and can take CO2 out of the atmosphere, potentially including that produced by natural methane or cement production. At present, the main obstacle is the complexity of the process, both technological and financial.

There are also challenges in distribution. The uneven distribution of renewables requires a significant expansion of electricity networks for long-distance transmission. The decentralised nature of solar panels will require new local electricity grids, as will charging networks for electric vehicles.

Measures not directly linked to electrification include the need to reduce emissions from agriculture, especially livestock farming, and the directly connected reduction in meat consumption in diet. It is also important to halt deforestation, since forests are an irreplaceable absorber of CO2 from the atmosphere.

The cost of investing in a transition including these and other solutions is currently estimated at between two and three percent of global GDP. Current investments are much lower, around 0.7 percent of GDP.

Martin Čopič concluded his lecture by saying that we must not forget that the climate crisis is a global issue and that the green transition must be just and, with the support of rich countries, reduce global inequality. He believes that the transition to a carbon-free society is not an economic issue but a question of the survival of human civilisation.