By trapping heat from the sun, greenhouse gases keep the Earth livable for humans and millions of other species. But now the amount of these gases has become too much, and this can radically affect which organisms and in which regions can survive on our planet.
Atmospheric levels of greenhouse gases are now higher than at any time in the past 800 years, and this is mainly because humans produce them in huge quantities by burning fossil fuels. The gases absorb solar energy and keep heat close to the Earth’s surface, preventing it from escaping into space. This heat retention is called the greenhouse effect.
The theory of the greenhouse effect began to take shape in the 19th century. In 1824, French mathematician Joseph Fourier calculated that the Earth would be much colder if it had no atmosphere. In 1896, the Swedish scientist Svante Arrhenius first established a link between the increase in carbon dioxide emissions from burning fossil fuels and the warming effect. Nearly a century later, American climatologist James E. Hansen told Congress that “the greenhouse effect has been discovered and is already changing our climate.”
Today, “climate change” is the term scientists use to describe the complex changes caused by greenhouse gas concentrations that affect our planet’s weather and climate systems. Climate change includes not only rising average temperatures, which we call global warming, but also extreme weather events, changing populations and habitats of wildlife, rising sea levels, and a number of other phenomena.
Around the world, governments and organizations such as the Intergovernmental Panel on Climate Change (IPCC), the United Nations body that keeps track of the latest science on climate change, are measuring greenhouse gas emissions, assessing their impact on the planet, and proposing solutions to the current climate. situations.
Main types of greenhouse gases and their sources
Carbon dioxide (CO2). Carbon dioxide is the main type of greenhouse gases – it accounts for about 3/4 of all emissions. Carbon dioxide can linger in the atmosphere for thousands of years. In 2018, the weather observatory atop Hawaii’s Mauna Loa volcano recorded the highest average monthly carbon dioxide level of 411 parts per million. Carbon dioxide emissions are mainly due to the burning of organic materials: coal, oil, gas, wood and solid waste.
Methane (CH4). Methane is the main component of natural gas and is emitted from landfills, the gas and oil industries, and agriculture (especially from the digestive systems of herbivores). Compared to carbon dioxide, methane molecules linger in the atmosphere for a short time – about 12 years – but they are at least 84 times more active. Methane accounts for about 16% of all greenhouse gas emissions.
Nitrous oxide (N2O). Nitric oxide makes up a relatively small fraction of global greenhouse gas emissions—about 6%—but it is 264 times more powerful than carbon dioxide. According to the IPCC, it can linger in the atmosphere for a hundred years. Agriculture and animal husbandry, including fertilizers, manure, agricultural waste burning, and fuel combustion are the largest sources of nitrogen oxide emissions.
industrial gases. The group of industrial or fluorinated gases includes constituents such as hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3). These gases make up only 2% of all emissions, but they have thousands of times more heat trapping potential than carbon dioxide and remain in the atmosphere for hundreds and thousands of years. Fluorinated gases are used as coolants, solvents and are sometimes found as by-products of manufacturing.
Other greenhouse gases include water vapor and ozone (O3). Water vapor is actually the most common greenhouse gas, but it is not monitored in the same way as other greenhouse gases because it is not emitted as a result of direct human activity and its impact is not fully understood. Similarly, ground-level (aka tropospheric) ozone is not emitted directly, but arises from complex reactions among pollutants in the air.
Greenhouse Gas Effects
The accumulation of greenhouse gases has long-term consequences for the environment and human health. In addition to causing climate change, greenhouse gases also contribute to the spread of respiratory diseases caused by smog and air pollution.
Extreme weather, disruptions in food supplies and an increase in fires are also consequences of climate change caused by greenhouse gases.
In the future, due to greenhouse gases, the weather patterns we are used to will change; some species of living beings will disappear; others will migrate or grow in numbers.
How to reduce greenhouse gas emissions
Virtually every sector of the world economy, from manufacturing to agriculture, from transport to electricity, emits greenhouse gases into the atmosphere. If we are to avoid the worst effects of climate change, they all need to switch from fossil fuels to safer energy sources. Countries around the world recognized this reality in the 2015 Paris Climate Agreement.
The 20 countries of the world, led by China, the United States and India, produce at least three-quarters of the world’s greenhouse gas emissions. The implementation of effective policies to reduce greenhouse gas emissions in these countries is especially necessary.
In fact, technologies to reduce greenhouse gas emissions already exist. These include using renewable energy sources instead of fossil fuels, improving energy efficiency and reducing carbon emissions by charging for them.
In fact, our planet now has only 1/5 of its “carbon budget” (2,8 trillion metric tons) left – the maximum amount of carbon dioxide that can enter the atmosphere without causing a temperature increase of more than two degrees.
To stop the progressive global warming, it will take more than just abandoning fossil fuels. According to the IPCC, it should be based on the use of methods of absorption of carbon dioxide from the atmosphere. Thus, it is necessary to plant new trees, preserve existing forests and grasslands, and capture carbon dioxide from power plants and factories.