The world on fire: why our planet heats up
Are humans responsible for climate change, or is it part of the millions-years-old natural cycle? What does this mean for us and other species on the planet?
More and more people concede that the weather has become too intense and erratic over the past decades. Climate scientists warn us about glaciers melting down and entire species changing their habitats—or, in the worst-case scenario, going extinct.
Why is it all happening right now? Well, the global climate is changing. You may have heard about “global warming” as one of the aspects of global climate change.
Compared to the 19th century, the average temperature across the planet has risen by 1.2 °C (about 2.2 °F)—turns out this minuscule change can have a profound effect. The climate has not necessarily become warmer in every place: it instead went to extremes, with nearly as many colder days as hotter ones. There are also a lot more catastrophic events, such as hurricanes, typhoons, and snowfalls.
Global warming is only one of the many climate-changing effects: other phenomena, like air pollution or the accumulation of plastic, might be more subtle. In any case, almost every climate agrees that humans have played a big part in what’s happening.
Like every living thing on the planet, we must now adapt to a newly emerging world. What will it look like? It is still quite hard to answer, but some of the predictions may sound alarming.
Here you will have some of your questions answered:
- What drives global warming?
- Did the planet change like this before?
- Did humans bring about global warming?
- What are its consequences?
- Can nature adapt to it?
- Can we stop it?
- What are people and governments doing to stop it?
What is “global warming” about?
People started to notice the trend for global warming (or, should we say more accurately, global heating) not so long ago. To put it simply, the trend is about the rise in the average temperature on Earth.
The serious talks began in the 1980s. After the scientists gathered overwhelming evidence that the trend is real, in 1989 they established the Intergovernmental Panel on Climate Change (which includes experts from more than 60 countries). It helped to attract people’s attention to the issue. However, the trend was noticed much earlier—it took decades to start acting upon the matter.
When was global warming noticed at first? Since the late 19th century, meteorologists (scientists who study weather) have been measuring average temperature each year. In 1938, based on the records from 147 countries, they were able to conclude that the average temperature, as well as the concentration of carbon dioxide in the atmosphere, had increased. Since then, it only continued to rise.
Later, they predicted that if the concentration of carbon dioxide doubles, the temperature may rise as much as 3 °C more. It was the time when we got our first concrete evidence—but the overall trend was predicted even earlier.
In 1896 chemist Svante Arrhenius suggested that the practice of burning fossil fuels for energy (which releases carbon dioxide in the atmosphere) might bring about global warming. He didn’t use this exact name—in fact, he studied ice ages, which are quite the opposite.
Arrhenius concluded that the concentration of carbon dioxide directly correlates with the temperature. This phenomenon is called the greenhouse effect, and it is the main driving force behind global warming.
The greenhouse effect: main driver of global warming
The term “greenhouse effect” was first used in 1901. But people have been studying it since the early 1800s.
Imagine a greenhouse—a place where people grow plants that need warmth. The air inside absorbs the heat energy from the sun through the glass roof—but then the roof would not let the warm air out, trapping the heat inside. For quite a long time, scientists have been observing this effect on a planetary scale.
The UV radiation from the sun is absorbed by the Earth’s surface, and some of the heat stays for good. As early as the 19th century, we knew that certain gases and vapors can make the effect stronger.
Today we know much more—especially as we are dealing with the consequences in the form of global warming.
Our planet’s atmosphere is like a giant roof of a greenhouse. Such gases like carbon dioxide, methane, and water vapor act like a blanket that keeps the heat inside the atmosphere.
The greenhouse effect is a natural process. Volcanoes, oceans, and living organisms release gases, which stay in the atmosphere. The process has always been happening as long as Earth had its atmosphere. In fact, if it weren’t for the greenhouse effect, the planet would be too cold to sustain any life. The greenhouse effect happens on other planets too. Venus has it so strong that its surface is heated almost to 500 degrees Celsius (900 Fahrenheit). The planet’s atmosphere is 96% carbon dioxide.
So, the greenhouse effect has been there for the entire Earth’s history. What’s relatively new is that in the past centuries humans have affected this process so much. Industrial activities, transportation, agriculture—all of these release large amounts of gases, and Earth doesn’t have the time to cool down like it always did.
What are the consequences of global warming?
Human activity has already caused many adverse effects on the environment—some of them are thought to be irreversible. So, how is life on our planet changing?
Climate change influences the weather patterns
Just as we mentioned at the beginning, the weather became more likely to go to extremes. Some of the planet’s regions experience too much rain and snowfall, whereas others suffer from severe heatwaves and forest fires.
These changes have been more frequent since the early 1900s. For example, throughout the 20th century, the average precipitation level in the USA has gone up, while tropical countries are more often hit with droughts.
It’s not just a common observation. Over the past twenty years, more than 300 scientific papers registered the increase in extreme cases of heat, rainfall, flooding, and droughts.
All in all, this change leads to shortages of drinking water, increased risk of wildfires, and crops losses.
Ice is melting
Glacier National Park in Montana, USA, had 150 glaciers in 1910. Today there are less than 30 left.
Ice caps are shrinking on both Earth’s poles—the Arctic region is at its warmest in the past 4000 years. Is it bad?
To put it bluntly: yes, very. First of all, polar bears and other arctic species lose their habitats and have to adapt to new conditions (we’ll talk about the adaptation a bit later).
But that’s not all! As glaciers melt, the water goes to the ocean—and the global sea levels have risen by roughly 20 cm (8 inches) since 1900 (the fact that hotter water takes more space also plays its part). In the future, it may rise even faster—up to 30 cm in the next 100 years.
There is one more side to this. Ice can absorb solar radiation, taking it away from the atmosphere. As glaciers melt, the area covered by ice decreases—thus less solar radiation is absorbed, and more of it stays.
It’s like a vicious circle! Global warming causes ice to melt. In turn, ice melting strengthens global warming, causing even more ice to melt.
Species become extinct
Scientists predict that up to 8% of animal species may go extinct because of climate change. Global warming (together with other climate change effects) can bring about a massive extinction event—there have been only five of these in the past 500 million years.
What’s alarming—this can be the first such event that happened due to human activity. Previous extinctions were caused by volcanic eruptions or meteorites.
Do you remember the crop losses? Animal extinction contributes to this as well. Global warming—combined with the use of pesticides—drastically reduces the number of insects in the fields. In Germany now there are 75% fewer insects in the fields than there were in 1990.
In most cases, this is good, but some of the insects are extremely useful. Common bees, for example, are responsible for the pollination of up to 70% of all seeds, fruits, vegetables, and nuts we consume. And bees are now undergoing a crisis—while still far from the danger of extinction, more and more beehives are lost every winter.
Oceans absorb carbon dioxide and heat up
The more gases we release into the atmosphere, the more they get absorbed by oceans, making them warmer. On the one hand, it helps to reduce the overall temperature. On the other hand, the chemistry of the ocean changes, disrupting marine ecosystems.
You might say that we live on land and what’s happening in the sea does not concern us—but the consequences could be as dire, as from increased sea levels, precipitation, and storms.
So, what’s the deal with marine species?
First of all, more heat leads to the blooming of algae on the ocean’s surface, which blocks the sunlight, reducing food to deeper-dwelling plants and animals.
Another fatal effect is the bleaching of coral reefs. The color of a coral polyp in the reef is dependent on algae that live on top of them—the polyp and the algae enjoy mutually beneficial relations. When algae die, reefs lose their color and become white—“bleached”. After that, the polyp begins to starve and may die as well.
Coral reefs are fragile yet extremely biodiverse ecosystems—occupying only 0,1% of all the ocean’s surface, they serve as a home for 25% of all marine species. They also protect shorelines from erosion and serve as popular tourist destinations.
From 1985 to 2012, the Great Barrier Reef off the Australian coast has lost half of its coral. Some scientists say that the reefs will never recover from this.
Some species living in the coral reefs were forced to migrate—and we don’t know at all if they would be able to survive global warming.