Perhaps you have ever watched documentaries about pretty polar animals threatened or tried to read complex scientific journals about forest fires, rising ocean level or fossil fuels. The causes of climate change are everywhere, from the clothes you wear to the hamburger you eat – but do you really understand the basics?
At CNN, we recently analyzed the most asked questions about climate change in Google Trends. the results revealed that many people are still searching for fundamental answers.
We have compiled this list to help you learn more about our changing climate.
The term "climate change" is used to describe a long-term change in global weather and climate patterns.
The Earth's temperature has changed dramatically over its 4.5 billion years of history, from the Huronian Ice Age that covered vast areas of the ice planet for nearly 300 million from years ago, to a period of about 50 million years ago, when scientists thought that palms and crocodiles were native to the Arctic Circle.
Today, the term climate change is commonly used to describe the effects of global warming resulting from human activity as a result of the industrial revolution of the 18th century.
Why is climate change happening now, what are the causes?
It's where it gets a little complicated.
The Earth's atmosphere is full of gas.
Some gases, including nitrogen and oxygen, which together account for 99% of gases in the atmosphere do not absorb the heat of the sun, allowing it to be reflected in the atmosphere. 39 space from the surface of the Earth.
Other gases, called greenhouse gases, including carbon dioxide, methane and nitrous oxide, absorb heat and constitute about 0.1% of the atmosphere. When these gases absorb solar energy, they send it back to the surface of the planet and other gas molecules, thus creating the greenhouse effect.
The greenhouse effect plays an important role in the natural regulation of the temperature of our climate. Without it, the average temperature of the Earth would be -18 ° C. It's about the temperature of a domestic freezer.
Since the industrial revolution, the concentration of greenhouse gases in the atmosphere is increasing due to human activities such as fossil fuel combustion, deforestation and modern agricultural practices. Which means more greenhouse and more heating.
A 2013 report by the International Panel on Climate Change (IPCC), a group of climate scientists from the United Nations, revealed that the concentration of carbon dioxide in the atmosphere had increased by 40% since the industrial revolution, resulting in an increase of 1 ° C in the temperature of the Earth.
What is the impact of climate change?
The impact of climate change depends on global warming.
In 2018, the IPCC released a critical report on the effects of a temperature increase of 1.5 ° C. These include more extreme weather conditions, sea level rise, the destruction of coastal ecosystems, the loss of species and vital crops, the displacement of the population and a huge cost to the global economy.
In 2018, the United Nations warned that without urgent action, global temperatures should exceed 3 ° C above pre-industrial levels by the end of the century.
At this temperature, the prospects are beginning to be even worse – entire oceans could engulf entire cities, plant and animal species risk extinction, their ecological systems failing to adapt to heat and hundreds of millions of people migrate due to coastal flooding, more durable air currents and exhaustion of yields.
Is climate change real or a hoax?
Almost everyone now accepts that the global climate is changing. The most important public debate – fueled by highly skeptical climate figures such as US President Donald Trump – addresses the question of whether climate change is caused by human activity.
But various studies have shown that a vast majority of scientists agree that climate change is real and caused by humans. One of them, 97% of scientists around the world, agrees that global warming caused by humans is occurring.
In 2014, 1,300 scientists from around the world contributed to a United Nations report (IPCC) on scientific knowledge of climate change. According to their report, there was a 95% chance that human activity over the past 50 years has directly resulted in an increase in earth's temperature.
The physical evidence of global warming has been noted worldwide, from the retreat of glaciers in the Himalayas to the bleaching of corals in our oceans, to the regularity of extreme weather conditions.
Can we stop climate change?
But there is hope.
Climate change can be limited and stopped, but only if we take what the IPCC describes as "rapid, profound and unprecedented change in all aspects of society".
To do this, two things must happen.
First, we must reverse 250 years of bad environmental habits. In December 2015, 195 countries agreed on a legally binding framework – the Paris Agreement – to achieve zero net carbon pollution by the end of the century. The immediate challenge is to slow down and limit global warming to "well below" 2 ° C from pre-industrial levels.
An essential aspect is to limit human practices that generate greenhouse gas emissions. This will involve changes in many aspects of our daily lives – from our diet to how we travel and how we make the products we all buy.
The second major challenge is to reverse the effects of these practices by reducing the amount of carbon dioxide (CO2) already present in the atmosphere. Advances have been made on this front, ranging from cutting-edge carbon capture technologies to simple tree planting. But until now, the IPCC has described the technology as "unproven" on a scale large enough to move the needle.