Our planet has never been warmer since the beginning of civilization. Since 2015, we have experienced the 5 hottest years on record. As climate change continues to be a reality, our present — and future — appear to be getting worse. So far, we have been discussing how the Industrial Revolution and human activities have been critical factors in increasing the world’s temperature.
Plus, we also mentioned the fact that scientists have already made their statement about the need to limit global warming to 1.5 °C by 2040. If we want a future with fewer extreme droughts, floods, tropical storms, and wildfires, among other devastating disasters, this is crucial.
Nine out of the ten warmest years since 1880 have happened since 2005. The effects of climate change are accelerating. To fight this, we need to know what’s causing it. So, what’s new in this article? We’ll delve into the causes of global warming, both human and natural. Although we must be clear about one thing: the natural ones cause a minor contribution to the damage that we’re seeing today. Human activities are the main cause of all the mess.
Ten causes of global warming
The rise in Earth’s average temperature is mainly due to the release of greenhouse gases into the atmosphere. That’s the strict definition of global warming. Of course, everything is not on just one gas. Many gases are contributing to global warming. Among them, you’ll find carbon dioxide (CO2), methane, nitrous oxide, and fluorinated gases.
Though you must note that CO2, generated by human activities, is the greatest contributor to climate change simply by its volume. By 2020, the atmospheric CO2 had increased to 48% above its pre-industrial levels, before 1750.
Want to understand better what global warming means? We have to check out how it works then. When these gases, like the ones we mentioned before, are released and collected in the atmosphere, they absorb sunlight and solar radiation. Radiation can’t easily escape into space and the gases end up trapping the heat and causing Earth’s temperature to get higher and higher. These gases are what we know as greenhouse gases, and their impact is called the greenhouse effect. The greenhouse effect is the main immediate cause of global warming.
But the greenhouse effect isn’t the only human-caused activity that boosts climate change. We also have, for example, the reflectivity or absorption of the sun’s energy. This is generated by activities such as agriculture, road construction, and deforestation. These cause more temperature extremes, and warming and cooling in populated areas. Why is that? Because those areas are full of buildings, pavements, and roofs, and they don’t reflect sunlight as much as natural lands do. This means that they absorb more heat.
As we said before, there are also some natural causes of global warming like natural cycles and fluctuations such as changes in the orbit around the sun. They have played a role in changing the climate for the last 800 thousand years. Nevertheless, human activities remain the main cause of global warming.
Ready to explore both sources of global warming? We’ll unpack ten human and natural causes of climate change so we can shift our routine to a more sustainable one and help others to do the same. We’re going to start with five human causes and then go into five natural ones.
1. Fossil fuels, energy, and more
This is a very well-known story if you’ve been following our latest blog posts, but let’s do a little recap. Burning fossil fuels like coal and gas generate the release of CO2 pollution into the atmosphere. Maybe you’re thinking that you’re not responsible for that but we kind of all are: we use fossil fuels as a source of energy for things such as creating electricity for our homes and powering our cars.
Power plants also use fossil fuels to work. This is particularly important because they burn fossil fuels and produce different types of pollutants that don’t only end up in the atmosphere, but also in the water. Therefore, they play a great role in climate change. Did you know that burning coal represents around 46% of carbon emissions?
If we discuss fossil fuels, we must bring oil drilling into the conversation. People use oil drilling to get petroleum oil hydrocarbons, but this process means a lot more than just that. When they drill for oil, they release other gases into the atmosphere.
These gases, such as methane that, contribute strongly to climate change. Plus, oil drilling is toxic for the wildlife and environment it surrounds. Before we move on, check this number out so you acknowledge how key it is to reduce fossil fuels in our lives: oil drilling is accountable for 30% of methane pollution and almost 8% of carbon dioxide pollution.
2. Deforestation
Deforestation and forest degradation account for up to one-fifth of global greenhouse gas pollution. So if we want to do a complete walkthrough of the main reasons for global warming, we must include deforestation. Plants and trees, and therefore forests, help regulate the climate by absorbing carbon dioxide from the air, storing it, and releasing oxygen back into the air. This shows that forests are a valuable support for reaching the 1.5 °C goal by 2040, and fighting climate change.
But there’s one more thing you should know: as trees absorb carbon dioxide, they transform themselves into carbon dioxide stores too. When we cut and/or burn them, we release CO2 into the atmosphere.
If they support carbon dioxide absorption and cutting them releases CO2, why do we keep on doing that? Well, deforestation is mainly caused by farming, urban infrastructure development, commodities such as paper, lumber, and palm oil as well as requirements of wood for homes and factories. And there’s more: we have to add soil erosion to the negative consequences of deforestation too.
3. Agriculture, farming, and fishing
To understand how agriculture, farming, and fishing contribute to climate change, we have to start by saying that methane, a greenhouse gas, is produced by, for example, animals and livestock, especially cattle. The same thing happens with agriculture and the fertilizers this activity uses.
Think about this: farming means that lots of green lands are taken and destroyed to build up a space to develop agriculture. It’s not only about the loss of green lands and how this can damage the local environment, but also about the fact that domestic animals produce plenty of greenhouse gases and tons of waste. This leads to farming being accountable for many of the climate change effects.
Fishing is also an activity that keeps generating pollution. Mainly, it is because of the fuel ships use to get into the sea and fish. The fact that there’s a huge number of people that buy and consume ocean animals, translates to more marine life being affected. This means there’s less diversity, and the quantity of marine life has also been significantly reduced.
4. Overpopulation
Overpopulation is defined as the incapacity of the Earth to carry a certain number of creatures. Statistics do not show that humans are going to live in more green lands and away from cities in the future. In fact, it’s quite the opposite: 56% of the world population now lives in cities and by 2050, seven out of ten people will live in cities.
An increasing human population means more people demanding food, more vehicles on the roads, more electricity for our homes, and therefore more atmospheric carbon dioxide. This means a greater contribution to climate change if we do not change our ways. Of course, this scenario will be real if we continue to follow the paths we’ve been following since the 19th century.
Why is that? Because in order to get the food we’ll need, we’ll have to depend on more transportation and more lands filled with animals and fertilizers. More demand for vehicles will mean more pollution released into the air; more demand for homes will encourage deforestation because we’ll need land to create new houses, schools, and colleges. These are just some future scenarios we might face if we don’t make a change.
5. Landfills: where the garbage goes
Have you ever thought about where your garbage goes when you throw it away? Most of it goes to landfills. Maybe you have seen a picture of big chunks of garbage that look stinky and dirty. They’re all over the world.
It’s not just about how bad they look, they are bad for our planet too. Our solid waste boosts greenhouse gas emissions. How? By generating methane from its anaerobic decay in landfills. Plus, we should add, the nitrous oxide emission that’s created in solid waste combustion facilities.
Possibly, you could be thinking, ‘those gases aren’t the main gases that contribute to climate change’. You’re right, but they’re even more dangerous. Methane has 21 times the warming potential of CO2, and nitrous oxide, 310 times. These gases are released by anaerobic decay and when the garbage is burned.
The next paragraphs outline natural causes that can contribute to climate change. These are the planet’s orbit and rotation, reflectivity, volcanic activity, and shifts in solar activity. We must emphasize though, that these natural causes contribute almost nothing to the current global warming crisis.
6. Melting of permafrost: when the cold meets the warm
First things first: What’s permafrost? Permafrost is a land that stays entirely frozen, therefore 0 °C or colder, for at least two years straight. They’re more common in higher latitudes and in areas with high mountains. For example, they constitute about 25% of the Northern Hemisphere.
Permafrost have trapped carbon dioxide, methane, and other greenhouse gases. Unfortunately, the last few years have seen large areas of permafrost thawing, releasing these gases. Icecaps and permafrost are melting at faster rates than ever before, boosting the gas emissions that those frozen grounds store.
7. Shifts in our planet’s orbit and rotation, changes in the seasons
Though orbit and rotation issues might sound pretty distant from our reality, the truth is that they aren’t. It’s been proven that the changes in Earth’s orbit and rotation had produced climate shifts in the past.
One great example is what happened in the Northern Hemisphere. The lack of summer sunshine was one of the primary causes of past cycles of ice ages. During those times, Earth suffered from long periods of cold temperatures known as ice ages where the average temperature at the coldest part of this age was about 11 °F (about 6°C) colder than it is today.
But our planet also suffered from shorter interglacial periods or periods between ice ages where the temperatures were warmer. During the peak of these periods, the average global temperature was 2 °F warmer than it is today.
8. Natural changes in Earth’s reflectivity and in carbon dioxide concentrations
Facts first: 70% of the sunlight that gets to Earth is absorbed. How is that possible? Well, dark objects and surfaces, such as the ocean, forests, and soil are more likely to absorb most of the sunlight.
That’s why in other blog posts, we have spoken about how the oceans get warmer due to climate change, while light-colored objects and surfaces, such as snow, ice, and clouds, are more likely to reflect the sunlight. Once ice and snow are melted or if there is less snowfall, then there is less reflection and, therefore, more absorption of heat.
Long story short: the amount of sunlight that’s absorbed or reflected depends on the Earth’s surface and atmosphere. Our planet’s surface changes not only because of human activities but also due to natural causes like the melting of sea ice that happened in the past.
There are also natural causes for the change in carbon dioxide concentrations. During the glacial cycles, carbon dioxide levels changed. For example, during the warm interglacial periods, CO2 levels were higher, and during cool glacial periods, those levels were lower.
9. Volcanic activity around the Earth
Volcanic eruptions have destroyed houses and taken thousands of lives. They have also contributed to increases in the levels of CO2 in the atmosphere. Actually, volcanoes are one of the greatest natural contributors to climate change.
Why is that? When they explode and spew particles into the upper atmosphere, they can reflect sunlight toward space and cool the surface of the Earth, that’s why their particles are known as an example of cooling aerosols. Want to meet one of those particles? Sulfur dioxide (SO2), a colorless, heavy, and toxic gas that has a pungent odor.
Despite this, volcano particles don’t remain in the atmosphere as long as the greenhouse gases produced by human activities. And, again, because we love facts, here’s an important one regarding this topic: human activities generate more than 100 times more carbon dioxide emissions per year than volcanoes do.
10. Shifts in solar activity
The Sun changes. But more precisely, what interests us is the fact that its energy output does too. This can have an effect on the intensity of the sunlight levels that get to the Earth’s surface. Even though these shifts have the power to make some modifications to our climate, the truth is that they don’t mean much, at least not in the past decades.
We can say that, because there are satellites that have been measuring the energy that the sun gives us since 1978. Taking the measurements of global average surface temperatures, and the Sun’s energy into account, we can see that, even though the sun has a natural 11-year cycle of small ups and downs in its intensity, there’s almost no effect on Earth.
How can we be sure about that result? Because over the same 11-year-cycle period, the average global temperature has increased, and can’t be connected with the Sun’s energy as a primary cause.
What can we do with all this information?
Identifying the causes of global warming may not mean much without checking out its results. We’ve explored some of them here and in other blog posts covering: longer and hotter heat waves, heavier rainfalls, warmer ocean temperatures, more frequent droughts, and stronger natural disasters like hurricanes.
That is what’s at stake. What’s in our hands? We have the power to change and help others join us on this journey. The first goal is connected to the fact that we need to cut our emissions. Scientists say that we have less than 8 years to reduce global carbon emissions by as much as 40% if we do not want to witness the worst impacts of climate change.
How can we achieve that goal? By embracing new habits that range from changing to renewable sources of energy to making the shift to more sustainable ways to buy, recycle, and throw products away. Need a guide to adopting these new habits? Find it in our recent blog post.
Plus, if you feel ready to join a sustainable tech community, see what we’re doing at Lemu. Get into Lemu, get into the change.
