Differences between global warming and climate change

The terms “global warming” and “climate change” are often used interchangeably. In scientific literature, climate change and global warming are inextricably linked, even if they are distinct phenomena. The simplest explanation of this link is that global warming is the main cause of changes in our current climate.

Here, we define these two concepts, describe how they are measured and studied, and explain the link between them.

What is global warming?

The Intergovernmental Panel on Climate Change (IPCC) has defined global warming as “an increase in the combined temperatures of the surface and the surface of the sea on the world and over a period of 30 years”. For more than a century, research has been carried out to measure and determine the precise causes of global warming.

Measures through history

The average surface temperature of the earth has increased and has dropped throughout the history of our planet. The most complete global temperature records, in which scientists have a high level of confidence, date back to 1880. Before 1880, observations came from farmers and scientists who, from the 17th century, recorded daily temperatures, precipitation measures and first and last frosts in their personal newspaper. These data have often proven to be precise in relation to instrumental data.

For long -term data, paleoclimatologists (scientists who study ancient climates) depend on historical variations in the number of pollen, the advance and withdrawal of mountain glaciers, ice nuclei, chemical alteration of rocks, trees of trees and locations of species, shore changes, sediments of lakes and other “proxy data”.

Scientists continuously refine the accuracy of the recorded data and how they are interpreted and modeled. Temperature records vary according to the region, altitude, instruments and other factors, but the more we get closer today, the more certain scientists concern the facts of global warming.

Natural events such as the impacts of asteroids and major volcanic eruptions, for example, can have dramatic effects on global temperatures, leading to mass extinctions. Cyclical changes in the position of the earth compared to the sun, called Milankovitch cyclesCan influence global temperatures and have long -term effects on climate over the thousands of years, although they do not take into account the short -term changes observed in the last 150 years.

Indeed, for the current era, a diagram emerges from data: the average temperature of the earth has increased much faster in the last 50 years than during any past warming event.

The greenhouse effect

From the middle of the 19th century, scientists began to identify changes in carbon dioxide concentrations as the main cause of world temperature changes. In 1856, the American physicist Eunice Fote was the first to demonstrate how carbon dioxide absorbed solar radiation. Its suggestion according to which “an atmosphere of this gas would give our earth a high temperature” is now the common understanding of scientists on the causes of global warming, the phenomenon now known as greenhouse effect. In other words, higher levels of carbon dioxide and other greenhouse gases in the atmosphere cause a warmer climate. Fote’s contribution was quickly overshadowed three years later by Irish physicist John Tyndall, who is generally recognized to first describe the greenhouse effect.

In 1988, James Hansen, director of the Goddard Institute for Space Studies de la NASA, could testify to the American Congress “with a high degree of confidence” that there was a “cause and effect relationship” between the greenhouse effect and the warming observed. Hansen spoke of recent global warming, but the “high degree of confidence” also applies to paleoclimatology. By their very existence, since the emergence of life on earth, carbon -based life forms have changed carbon dioxide levels in the atmosphere.

Causes induced by man

Humans have caused the fastest and most serious changes in global temperatures. Since the testimony of James Hansen in 1988, the level of confidence in anthropogenic causes (induced by man) of global warming has become functionally unanimous within the scientific community.

These anthropogenic causes are not new. As early as 1800, the naturalist Alexander von Humboldt observed how deforestation increased regional atmospheric temperatures. Like forest fires today release tons of carbon dioxide in the atmosphere, controlled burns have been an additional source of carbon for centuries.

These traditional practices, however, are overshadowed by the number of greenhouse gases issued since the beginning of the end of the 18th century with the development of the coal steam machine. The combustion of coal has extended from a hundred times in the 19th century, increased by 50% in 1950, tripled between 1950 and 2000, then almost doubled between 2000 and 2015. Oil consumption followed an even faster growth curve, increasing 300 times between 1880 and 1988, then increasing by 50% to 2015. The use of natural gas has increased the fastest, increasing thousand times between the 1880 late and 1991, 1991, then other.

The combustion of fossil fuels, which emits greenhouse gases mainly from carbon dioxide, methane and nitrous oxide, can have culminated in 2017, but still represented 82% of the main consumption of global energy in 2021.

The parallel growth in the consumption of fossil fuels and the increase in overall surface temperatures is striking. Greenhouse gas emissions have reached levels that are “unprecedented at least in the past 800,000 years” and are “extremely likely Having been the dominant cause of warming observed since the middle of the 20th century, ”according to the IPCC.

A simple way to understand how fossil fuels contribute to global warming is to think of a cover. The combustion of fossil fuels has wrapped the earth in a pollution cover, which imprisoned heat. The more fossils are burning, the thicker the blanket, the more the heat can be trapped.

What is climate change?

The climate is time for a long time. Changes in the climate created by global warming induced by humans have and will continue to have long -term effects. These effects, once considered to be in the near future, are increasingly visible today, the most apparent changes being weather changes. But more subtle changes to whole ecosystems also have a very serious threat.

Extreme time

Global warming has made the weather wilder and more unstable, as natural disasters have shown “exponential increases in recent decades” both in intensity and frequency. Natural disasters “once in a century” such as forest fires, dead heat waves, droughts, floods, tropical storms, hurricanes, blizzards and avalanches have increased 10 times since 1960.

According to the world meteorological organization, over the past 50 years, half of all recorded disasters and 74% of related economic losses are due to weather, climate and water risks such as floods.

Assign time to climate change

It is often difficult to assign an extreme meteorological event particular to global warming. The natural variability of the climate is responsible for short -term changes from one year to the next in weather conditions, especially at the regional level. But the long -term model of meteorological events reveals the hand of climate change.

What can be attributed to global warming is a changing climate, where the warmer and warmer oceans increase the probability and intensity of droughts, heat waves, storms, hurricanes and other extreme weather events. The allocation of extreme events is more a question of probability than certainties, since the circumstances involved often have no historical precedent.

But by comparing current extreme events to historical events of different intensities and different atmospheric conditions, scientists can give increasingly rigorous explanations of the role that global warming has played in the worsening of extreme weather conditions.

Although there is often a disagreement within the scientific community on the level of influence of climate change on a single extreme event, there is a solid agreement according to which climate change induced by man plays a leading role.

Threats to ecosystems

Damier disasters than natural disasters are the threat of climate change for the whole biosphere of the earth, the ecosystems that support life. The species that try to adapt to the changing climate often fail.

Coral, for example, dies while the oceans absorb atmospheric carbon dioxide and become more and more acidic. When peat bogs and coastal wetlands dry due to the rise in temperatures, their dead vegetation decomposes more quickly and releases greenhouse gases, contributing to a “cascade effect” where calamity contributes to the next. The “tilting points” climate -oriented, already underway, lead to major losses of biodiversity and undermine whole ecosystems.

Climate change research always contains unknowns and uncertainties. It is easier to understand the past than to predict the future of the physical and biological systems of an entire planet. However, key uncertainty concerns less the hard science of climate change and more on the social sciences in which humans react to it.