Energy Sources & Climate Change
The First Law of Thermodynamics states that energy cannot be created or destroyed, it can only be transformed. On planet Earth, all available energy comes from one of three primary sources: solar, nuclear and geothermal. Throughout history, humans have converted this energy into useful forms like heat, motion or electricity. Climate change is strictly related to this energy conversion process.
First, let's take a closer look at the three energy sources available to us.
Solar Energy
The sun generates massive amounts of energy that reaches the Earth in the form of sunlight. That energy heats our planet and powers processes like the water cycle, wind patterns, and - through photosynthesis - all living things. There is plenty of solar energy to go around. Our planet receives about 173,000 terawatts (TW) of solar power continuously, which is around 10,000 times the entire human energy consumption.
Nuclear Energy
This source of energy comes from atoms. Certain atomic elements can be split (fission) or joined (fusion) and these processes release vast amounts of energy, which can be captured and transformed into heat. Humans have mastered the splitting process using uranium. Reserves of uranium should allow us to generate power for another 230 years at current consumption rates. Nuclear fusion is not yet available, but if harnessed it could provide us with abundant energy for millions of years.
Geothermal Energy
Geothermal energy is derived from planet Earth's internal heat. Some of this energy escapes toward the surface, driving natural phenomena like volcanoes and geysers. The total heat stored in the Earth's crust is immense, but the portion accessible for human use is much smaller. Current estimates suggest geothermal could sustainably provide about 100 TW by 2050.
Although these sources are not infinite, each of them can provide amounts of energy far greater than we need in the foreseeable future. Right now, we consume about 15-20 terawatts per year. None of these sources is inherently clean or dirty either—that depends on how we transform them for our needs.
Energy Sources Used Today
We rely on various methods to transform energy from these primary sources into a form of energy that is useful for us.
Energy Sources Derived from Solar Energy
Today, most energy is obtained from fossil fuels. Fossil fuels are essentially solar energy stored underground originating from ancient plants and animals that captured sunlight millions of years ago. They are extracted in the form of coal, oil and natural gas. Fossil fuels currently account for about 77% of all human energy use.
The next category are the renewable sources that consist of solar energy captured from air, water and directly from sunlight. Turbines capture energy from the movement of air, hydropower relies on the flow of rivers and photovoltaics convert sunlight directly into electricity. Together, they provide approximately 15% of global energy.
Plants and trees are also a form of stored solar energy which can be converted to other forms in the process of burning. Biomass, as it is called, is used to provide around 5% of total energy. It is also the oldest source of energy known to man. Humans started burning wood to keep themselves warm and to cook food around 2 millions years ago!
Energy Derived from Other Sources
We get most of our energy directly or indirectly from the sun. The two other sources play a minor role. Nuclear energy accounts for roughly 4% of global use. Geothermal is even less used and covers less than 1% of global energy needs.
The Problem with Fossil Fuels
Fossil fuels are our main energy source and we convert them in the process of burning.
Refined oil is burned by engines that move cars, trucks, airplanes, and ships. Natural gas and coal are burned in power plants in order to generate electricity and heating. Fossil fuels are also burned in the process of creating fundamental materials such as steel, fertilizers, and plastics.
All this burning generates a lot of CO2 emissions. In 2023, we released 36.8 billion metric tons of CO2 into the atmosphere. Those vast quantities of CO2 warm the planet and cause climate change, leading to consequences ranging from very inconvenient to outright catastrophic.
Solution
Media, scientist and climate activists constantly remind us about the terrifying consequences of climate change. That is understandable, however the discussion often leaves out the solution part and focuses on who to blame for where we are. The typical culprits include oil companies, politicians, billionaires or people driving SUVs. As a result, we become angry, frustrated and feel powerless. Eventually, this leads to apathy and many of us decide to ignore the problem altogether and move on with our lives. I know, I've been there.
But what if we see climate change as the great challenge it is, but one with an obvious solution? We need to minimize the amount of fossil fuels that we burn by getting our energy from places that do not generate CO2 emissions. This is a clear, simple and actionable statement.
Once I understood that basic premise, pessimism and frustration gave way to cautious optimism. Yes, we have to transform the global energy system and rebuild a large portion of our infrastructure. This is going to be very hard but the driving force behind all human progress is our creativity and ingenuity. Which is great, because this is exactly what we need in this case.
From this perspective, fixing the climate through energy transition is a fascinating journey for humankind. The best news is that this process is already underway!