Humans emit approximately 51 billion tons of greenhouse-gas (GHG) emissions globally, the majority of which come from energy consumption which keeps on increasing every year. To reduce the impact of these emissions to an exemplary level, one must apply the sustainable tools the planet Earth already has in smarter and faster ways.
Emissions Today
Whenever someone tries to have a conversation about climate change, the one quote that they should remember is “The coldest year in the future will be hotter than the warmer year in the past.” What does this mean to people living in this world? Well, humans emit roughly 51 billion tons of GHG emissions per year. GHG includes carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFC) etc. Overall CO2 concentration in GHG emissions is 37 billion tons in a year. Each GHG has a different tendency to trap heat in the atmosphere; the 52 billion tons of GHG in a year is the figure that is referred to as CO2-equivalent (Gates, 2021) .
To those observing the data on GHG in the atmosphere from the Pre-Industrial Era until today, it isn't hard to determine that these voluminous emissions have been coming from extraordinary consumption of fossil fuels (coal, oil, natural gas). Fig. 1 depicts the total GHG emissions of the world in a year by sector.
To understand how emissions remain in the atmosphere and raise Earth's temperature, we must look at physics and chemistry. The natural greenhouse effect is a good thing, otherwise our planet would have been unbearably cold.
Fig. 2 shows how the greenhouse effect works. The sun’s radiation comes to the Earth as ultraviolet radiation and warms up the planet until the radiations are emitted back by the Earth, following the principle of “blackbody radiation.” The radiation emitted by the Earth has the specified wavelength which gets trapped into the GHG present in the atmosphere, then these GHGs absorb all the energy of these radiations which makes its molecules move faster. The faster the gas molecules, the hotter they become, which as a result increase the overall temperature of the planet (Vellalassery et al., 2023) .
So far, the Earth’s average temperature has increased by 1°C, and the world is witnessing floods, wildfires, and water scarcity (Hansen et al., 2020) . If the combined effort is not executed to reduce these emissions, the overall temperature may rise to 3–4°C by mid-century and 8–9°C by end of the century (Gates, 2021) , which may have devastating effects such as extinctions of a few vertebrate animal species, increased risks of drought, rise in sea level resulting in urban flooding, risk to the survival of food crops, etc. Each country should make it a priority to reduce GHG emissions and limit the increase of the overall global temperature to 2°C as per the Paris Agreement (Barzagli & Mani, 2019).
Making Carbon-Free Electricity
Referring again to Fig. 1, the generation of electricity represents only 26% of worldwide emissions, but generating green electricity not only eliminates coal-fired and natural-gas power plants, but can also pave ways to electrify more things which are needed in the future (e.g., electric vehicles, electric heating, and cooling systems, using electrified systems in industry and agriculture, and more). Fig. 3 represents the world's electricity generation by source.
This leads us to discuss what options planet Earth has to generate and store green electricity to reduce GHG emissions. Solar and wind energy sources are capable of doing so, but their major drawback is intermittency. For example, Germany, which produced a significant amount of solar power in June, saw reductions in power generation by a factor of 10 in December due to seasonal variations (Gürtler & Paulsen, 2018).
Nuclear fission, which generates electricity by the splitting of atoms, may be the closest option to provide energy both day and night but it has drawbacks related to the safety of human lives and infrastructure. Also, uranium which is the fuel for the nuclear fission process, can be used to make nuclear weapons. Moreover, nuclear waste is also dangerous and remains radioactive for many years. In spite of its great contribution to nuclear engineering, and in answering questions of the stability of superheavy elements in the nuclei, the phenomenon of nuclear fission remains shrouded in mysteries (Schunck and Regnier, 2022).
On the other hand, nuclear fusion, which generates energy by fusing atoms, is a comparatively more convenient option than nuclear fission. The fusion process uses hydrogen as its fuel, has no chain reactions, and has no prolonged safety considerations linked to it, unlike nuclear fission.
To date, reviews of recent nuclear fission designs are lacking in practical application. After serious experimentation of the fusion process in the 1950s, the public’s enthusiasm in media created a picture that this technology was going to be available in a few years. However, at that time no one knew the complexity of the physics involved in designing the reactor; this is one of the reasons we do not have any commercial reactor yet.
We do, however, have a clearer idea of what we need to achieve. At the moment, the energy required to initiate the fusion process (e.g., heating hydrogen atoms at a temperature of 50 million°C) is greater than the energy generated in return (Meschini et al., 2023).
Energy-Storing Options
Now let's talk about storing energy in batteries which has always been considered an expensive option. Researchers have tested different materials; some have used liquid instead of solid metals, while some are considering a flow battery system as an option. But the chance of improvement is slim considering our energy needs at a low cost (Dehghani-Sanij et al., 2019) .
Producing hydrogen and compressing and storing it in fuel cell batteries is another option, but producing hydrogen through electrolysis is an expensive option, and using it again for electricity may incorporate many losses in the process. Other options include thermal storage in which materials like molten salt can be used to store heat when demand is low, and this heat can be used at later stages to generate electricity during peak time. Another option is pumped hydro technology where water can be pumped at the top of a hill to a reservoir when electricity is less expensive and later can be run down to power a turbine.
Innovations and Green Premiums
In addition to these technologies, other innovations are needed to make a bigger impact in making the planet Earth green and emissions-free, but even promising technologies currently cannot compete with fossil fuels. Because of this, the additional cost of using these technologies, which is referred to as “green premium,” needs to be evaluated seriously, and technologies with lower green premium should be adapted instead of using finite resources of fossil fuels.
Some technologies might have negative green premiums, for example, in some specific areas of Iceland, generating electricity from geothermal sources is less expensive than using grid electricity (Titus et al., 2022). Even after adapting technologies with green premium, consumers won’t be willing to pay additional costs. This is why it’s important for the government to provide incentives that start the process of using these sources.
Conclusion
Keeping in mind all of these innovations and alternative energy options that are needed to decarbonize the planet Earth, we don’t need all of these to pan out to reverse the effects of climate change. Some of the innovations overlap each other, for example, if it is possible to produce cheap hydrogen there is no need for a magic battery breakthrough, similarly if an energy source is providing cost-effective and reliable power there is no need for green premium.
Conclusively, there is an obvious threat of climate change and its severe implications upon us, which is hard to undo in a short amount time, therefore one has to always remind themselves what Hans Rosling has said in his book Factfulness: “When we have a fact-based worldview, we can see that the world is not as bad as it seems, and we can see what we have to do to keep making it better.”
For Further Reading
The Increased Anthropogenic Gas Emissions in the Atmosphere and the Rising of the Earth’s Temperature: Are There Actions to Mitigate the Global Warming? by F. Barzagli, University of Florence; and F. Mani, ICCOM CNR. Substantia.
BP Statistical Review of World Energy 2022, BP.
CO₂ and Greenhouse Gas Emissions—Our World in Data
Study of Energy Storage Systems and Environmental Challenges of Batteries by A. Dehghani-Sanij, University of Waterloo.
How To Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need by B. Gates.
Review of Commercial Nuclear Fusion Projects by S. Meschini, Massachusetts Institute of Technology.
Theory of Nuclear Fission by N. Schunck, Lawrence Livermore National Laboratory.
The Effect of Wind and Solar Power Forecasts on Day-Ahead and Intraday Electricity Prices in Germany by M. Gürtler, Braunschweig Institute of Technology.
Global Surface Temperature Change by J. Hansen, NASA Goddard Institute for Space Studies.
The Projected Timing of Climate Departure from Recent Variability by C. Mora, University of Hawai‘i at Mānoa.
Carbon-Negative Geothermal: Theoretical Combined Geothermal-BECCS Injection Cycle by K. Titus, D. Dempsey, and R. Peer.
Nuclear Fission by R. Vandenbosch.
Greenhouse Gas Effects on the Solar Cycle Response of Water Vapor and Noctilucent Clouds by A. Vellalassery, Leibniz Institute of Atmospheric Physics at the University of Rostock.
