Our life exists on Earth only because of the natural greenhouse effect. That remarkable phenomenon has given us an average temperature of around 18ºC rather than -15ºC. The problem is that climate change arrived.
What was meant to be a beneficial phenomenon has become a major reason for human extinction. The climate has always changed, but over the past 150 years we have added an anthropogenic greenhouse effect to what was a natural one.
And what is the great threat in this shift in climate? The extreme weather events that come out of it. Read on and get a fuller sense of the threat (and how to fight it)!
What is climate change, and what is the greenhouse effect?
“Broader than just global warming, climate change is a series of shifts that could make human life unsustainable.”
What is climate change? Well, it is certainly a great deal more than global warming alone, which is about rising temperature. Climate change involves temperature, rainfall intensity and extreme weather events.
It has occurred naturally throughout the life of the planet. Geological evidence shows that the global average temperature has been both far higher and far lower than it is now (18ºC).
The problem is that climate change used to happen over a very long span of time, the current period of warming is happening far too fast. To understand that better, we need to talk about the greenhouse effect.
What is the greenhouse effect?
In a greenhouse for plants, sunlight comes in through transparent glass walls. Only part of that light is absorbed by the plants and the soil, the rest is reflected back as radiation.
And of the light that comes back, only part actually escapes through the glass; the rest stays inside. That raises the temperature inside, which keeps the plants warm.
The Earth works in a similar way:
- Energy from the sun passes through the Earth’s atmosphere and is partly absorbed by plants, soil and the oceans.
- The rest of the energy is reflected back, but not all of it, some is held by gases in the atmosphere (the greenhouse gases).
- That produces the climate that makes this great planet habitable for us living things.
That is the natural greenhouse effect, something good for us. But do you know what is not good? The anthropogenic greenhouse effect.
When does the greenhouse effect start to become a problem?
The global warming anomalies we are witnessing are, in part, our fault. Around 15 years ago, data produced by various scientists for the IPCC report found that 97% of global warming comes from the anthropogenic greenhouse effect.
This artificial greenhouse effect started to become more pronounced from the first industrial revolution onwards. At that point, human beings began putting millions of tonnes of carbon dioxide and other gases into the atmosphere.
As a result, the amount of CO² in the atmosphere doubled against the minimum values of the last 700,000 years. Over time, we have managed to come up with yet more ways of intensifying the anthropogenic greenhouse effect.
And the result is…
Over the past 150 years, the global average temperature has risen by 2ºC. Sounds like very little, does it not? And yet the difference between today’s global average temperature and that of the ice ages is only 5ºC.
Bear in mind that it takes an enormous amount of heat to raise the Earth’s average temperature, even by 2ºC. Staying below a 2-degree rise is essential if we are to avoid extreme weather events.
The results of that increase are already being felt: the world’s 10 hottest years have all been recorded since 1998. On top of that, we are at a temperature 1.15ºC above the pre-industrial average.
What causes climate change?
There is no single cause of climate change, and most of them involve human activity. Some of the reasons for climate change are:
- Landfill sites;
- Burning fossil fuels;
- Livestock farming;
- Use of high-carbon transport;
- Excessive use of fertilisers;
- Food waste.
All of these end up emitting greenhouse gases, only in excess. Those gases are carbon dioxide, methane, nitrous oxide and fluorinated gases.
The more gas there is in the atmosphere, the greater the impact on it, damaging the invisible layer that protects us and letting heat through unfiltered, so that it is felt more intensely.
A closer look at where the heat comes from
One of the major causes of climate change is burning coal, oil and gas, which produces carbon dioxide and nitrous oxide. Deforestation should also be named, since trees play a part in regulating the CO² in the atmosphere.
When trees are felled, the carbon stored in them is released into the atmosphere, which reinforces the greenhouse effect.
The growth in livestock farming is another major reason for methane appearing in the atmosphere. That gas is produced by cows and sheep after they digest what they eat.
Finally, the fluorinated gases emitted by equipment and products can have severe consequences: their warming effect is up to 23,000 times stronger than that of CO².
Who are the main culprits?
Looking at greenhouse gas emissions by economic sector, it is possible to name different culprits. According to the E.P.A. and climate.gov, the biggest emitters are:
- Electricity and heat production, at 25%;
- Agriculture, forestry and other land use, at 24%;
- Industry, at 21%;
- Transport, at 14%;
- Other forms of energy, at 10%;
- Buildings, at 6%.
What are the consequences of climate change for humanity?
The impact of climate change is plain, and it is something the IPCC report points to constantly. Arctic sea ice, for example, has shrunk by an average of 12.85% every 10 years.
Another glaring example is the heat already mentioned, the last 7 years, from 2015 to 2021, were among the hottest ever, as with the extraordinary record of almost 50ºC reached in Canada in 2021. The result has been “fire seasons” that have grown longer and more intense, as seen in Australia in 2019.
So what are the main consequences of climate change?
More extreme weather events
Weather events are not only recurring more often, they are also becoming more intense. Floods, storms, droughts, hurricanes, all are starting to become more common.
One example is El Niño, which tends to occur every 5 to 7 years and brings severe droughts and torrential rain (depending on location). It is expected to become more frequent over time.
Rising sea levels
By the end of the 21st century, sea levels are expected to rise by 18 to 59 cm. That could see many islands disappear (island nations among them) and will do a great deal of damage to coastal regions.
Less ice cover
Since 1990, one of the major consequences of climate change has been the loss of ice cover. The Arctic has lost around 7% of its cover since then, and that loss is expected to accelerate there and in the Antarctic.
Severe changes in ecosystems
Climate change naturally brings changes in ecosystems, which puts the survival of countless species at risk. Some examples:
- Fewer flowers and fruit produced in the Amazon;
- Extinction of endemic species;
- Growth in vector populations (the organisms that can transmit infectious diseases between humans and animals), leading to zoonoses, diseases or infections naturally transmissible between vertebrate animals and humans, such as malaria and dengue.
Desertification
Human activity and climate change are the main drivers of desertification. It is expected that 135 million people will be at risk of losing land as a result.
Air pollution
As temperatures rise, stronger air pollution naturally follows, created by cars, aircraft and factory emissions. The hotter your surroundings, the more pollution appears.
And there is extreme cold too!
Remember when I said climate change is not only global warming? Well, it turns out these shifts also lead certain areas to experience a colder winter than normal.
That happens because higher temperatures in the Arctic cause violent swings in the polar jet stream. Larger swings send cold air further south.
And how do we fight climate change?
Fighting climate change is nothing new. In December 2015 the Paris Agreement was signed, a worldwide commitment to the adoption of climate policies by different governments. The objective? Cutting greenhouse gas emissions.
It was signed by 195 countries, which committed to the target of keeping global warming below 2ºC (limiting it to 1.5ºC). Beyond the Paris Agreement, though, what can you do?
- Cut your waste, since landfill sites are a major source of methane emissions;
- Cut the number of disposables in your daily life;
- Compost your food waste, keeping it out of landfill;
- Limit how many animal products you consume;
- Help reduce our dependence on fossil energy;
- Advocate for the cause, holding companies and political figures to account for their positions and actions.
Fighting climate change is a collective act. It is not only about doing good things yourself. You need to join with other people against this great threat. Start today and feel the positive effects later!
