Global warming: the latest shock report from NOAA

Greenhouse gases, ice Arctic, mountain glaciers, ocean temperature, sea level rise, spring snowfall, global temperature and solar cycles are the main elements studied by the NOAA to determine the state of the climate. the US administration report delivers overwhelming data on the state of our planet.

Greenhouse gases: a continuous rise

In 2020, the heat generated by all greenhouse gases from human activities was 47% higher than that of 1990. emissions carbon dioxide, methane, nitrous oxide and other similar gases have only increased over the past 30 years. And this, despite the global crisis linked to pandemic of Covid-19 which shut down many sectors of activity for a few months. In the image below, we can clearly see that the trend of the curve is constant and regular: the efforts of certain nations for the development of green energies are clearly not sufficient, and not even significant, on the overall scale of the results from 1980 to 2020.

Carbon dioxide: an unprecedented increase

The carbon dioxide concentration (main greenhouse gas) in the atmosphere has increased by 45% since the start of the use of fossil fuels. The curve, below, shows a frantic rise that nothing seems to stop since 1960. The sawtooth curve represents the concentration of ppm (parts per million) and the second curve in the middle (solid line) is the 12-month average trend.

This second graph of the evolution of the carbon dioxide concentration can be confusing: the presence of this greenhouse gas in the atmosphere has indeed undergone fluctuations over time, however the time scale changes. from year 0: there is an ultra-rapid increase in the space of 2020 years, while the previous increases were spread over … 200,000 years!

Melting Arctic ice: almost half in 30 years

Since satellite estimates began in 1979, the ice surface covering the ocean Arctic by the end of summer (the “ice minimum”) has declined by more than 40%. Over the summer period 1979-2020, the ice surface covered on average 15% of the Arctic Ocean: since 1980, this ice surface has decreased by 13.1% per decade, according to data from the National Snow and Ice Data Center.

Recall that the melting ice cream is one of the most important global warming. If this melting seems geographically distant and far from our daily concerns, it should be noted that ice is essential for the regulation of weather global. Thanks to their color white, they reflect 95% of the rays of the Sun, which keeps temperatures low on site, but they also have an effect on temperatures in the rest of the world.

The retreat of glaciers in the mountains

Since 1980, the rate of melting mountain glaciers doubles every decade. The dizzying curve of the World Glacier Monitoring Service’s Climate shows the evolution of glaciers in the space of 50 years. From 1970 to 2020, the world’s glaciers each lost an average of 27.5 meters of ice water. Among the world’s most threatened glaciers, the himalayan glaciers : according to a UN report published in June 2021, the Hindu Kush and the Himalayas will lose two thirds of their volume ice by 2100, if current trends in gas emissions remained the same. This mountain range, which we call the “third pole”, could cause shortages of water and food for 1.7 billion people who live in its river basins: Afghanistan, Tibet, Pakistan or even Nepal are supplied with water by these glaciers.

Ocean temperature: exponential rise from 2000

NOAA estimates oceans have gained between 0.58 and 0.78 watt of thermal energy per square meter between 1993 and 2020. Theocean temperature rise contributes to rising sea levels, melting ice and degradation of corals. The curve shows the evolution of the heat of the oceans measured in the 800 meters depth below the surface, in comparison with the average temperature from 1955 to 2006. The temperatures rose radically above the averages from the middle of the 1990s, before a real explosion of heat from the 2000s.

Globally, the ocean surface has warmed by more than 0.1 ° C per decade since 1971. Even more, this rise in temperatures is not perceptible only on the surface, since a rise in temperatures has been found to a depth of at least 3,000 meters.

Sea level rise: record in 2020

The water has risen an average of 20 to 22 centimeters since 1880. The speed of this rise in water level more than doubled between 2006 and 2015 compared to its speed of elevation during XX^e century. The curve, below, represents the rise in water level, both with sea measurements (in light blue) and satellite measurements (in dark blue). In 2020, the average sea level reached a new record: 91.3 mm (9.1 cm) higher than in 1993.

According to one study published in Environmental Research Letters, more than 510 million people currently live in areas that will ultimately be located below sea level if global warming remains at +1.5 ° C compared to the pre-industrial era. A threshold that will be reached around 2030, according to the IPCC.

Since 1993 satellite data, sea levels have risen absolutely all over the world. On the map below, the areas in dark blue are those that have seen their level increase the most: in particular the North Pacific off Asia, the Atlantic off North America, and the Atlantic South off Argentina.

Spring snows in retreat for 20 years

Since 1967, spring snowfall has declined 1.4% per decade in April, 4.1% in May, and 12.9% in June. The graphic, below, shows theanomaly, in millions of kilometers, between snow-covered surfaces each year from April to June, compared to the 1981-2010 average. For 20 years, almost every spring has found itself below average in terms of the extent of snow-covered areas. Spring snow is very important for the biodiversity : its extent, and its melting in summer, irrigates plants, fills rivers, provides water points for wildlife and also has an impact on the season fires.

Global temperature: +1 ° C since the 19th century^e century

The global temperature is that which combines the average temperature of the earth and the mean ocean temperature. The global temperature of the Earth has undergone an unequivocal increase, as seen on the curve below of the temperatures recorded from 1880 to 2020, compared to the average of the XX^e century. The rate of warming has more than doubled since 1981. Since the end of the XIX^e century, the global average temperature has increased by almost 1 ° C.

On the NOAA planisphere, we note that the Arctic Ocean has undergone the greatest temperature rise, followed by the North Atlantic Ocean, Asia and Russia.

Solar cycles: too weak to explain the warming

NOAA believes that the brightness of the Sun varies by 0.1% on average over the solar cycles that each last 11 years. During the past century, the variations have been minimal and its consequences on Earth very limited. None of these variations in solar activity is therefore sufficient to explain the current global warming according to NOAA.