Right now, life is thriving on our oxygen-rich planet, but Earth wasn't always this way, and scientists predict that in the future, the atmosphere will become rich in methane.
This probably won't happen for another billion years or so. But when change comes, it will happen very quickly, according to a disturbing study.
This transformation will return the planet to something similar to the state it was in before what is known as the Great Oxidation Event (GOE) about 2.4 billion years ago.
Moreover, the researchers behind the study say that atmospheric oxygen is unlikely to be a permanent feature of habitable worlds in general, which has implications for our efforts to detect signs of life farther out in the universe.
A sharp decline in atmospheric oxygen may be induced to levels reminiscent of ancient Earth, before the onset of humid greenhouse conditions in the Earth's climate system and before the significant loss of surface water from Earth.
At that point, it will be the end of the road for humans and most other life forms that depend on oxygen to survive.
To reach their conclusions, the researchers conducted detailed models of Earth's biosphere, taking into account changes in the sun's brightness and the corresponding decrease in carbon dioxide levels, as the gas is broken down by increasing heat levels. Lower carbon dioxide means fewer photosynthetic organisms such as plants, which can lead to lower oxygen.
Scientists previously predicted that increased radiation from the Sun would wipe out ocean water from the face of our planet within about 2 billion years.
“The decline in oxygen is very sharp,” said Earth scientist Chris Reinhard, of the Georgia Institute of Technology. “We are talking about a million times less oxygen than there is today.”
According to calculations by Reinhard and ecologist Kazumi Ozaki, of Toho University in Japan, Earth's history of being rich in habitable oxygen could ultimately only last 20 to 30 percent of the life of the planet as a whole — and microbial life will persist long after we're gone.
The research was published in the journal Nature Geoscience.
Earth passes a terrifying major global warming threshold for the first time
On Friday, November 17, our planet briefly crossed a key warming threshold for the first time since the start of instrument records, the consequences of which climate scientists have warned are dire.
Preliminary data showed that average global temperatures were more than 2 degrees Celsius (3.6 degrees Fahrenheit) above the historical average, from a time before humans began consuming fossil fuels and emitting greenhouse gases that lead to global warming.
This does not mean that efforts to limit global warming have failed so far, as temperatures must exceed 2 degrees Celsius for several months and years before scientists consider this a major threshold crossing.
But scientists pointed out that the temporary exceedance recorded on Friday is a stark reminder that the climate is moving into uncharted territory.
Friday was the first time that daily fluctuations around global temperature standards, which have been increasing steadily for decades, pushed the planet beyond the danger threshold.
This came after months of record warmth that stunned many scientists, defying some predictions about how much temperatures would accelerate this year.
Global temperatures on Friday were 1.17 degrees Celsius (2.1 Fahrenheit) higher than the 1991-2020 average, Samantha Burgess, deputy director of the European Union's Copernicus Climate Change Service, said Sunday on the social media platform X. It is a standard margin.
She added that given the amount of human-caused global warming during that period, this means the average global temperature on Friday was 2.06 degrees Celsius (3.7 Fahrenheit) higher than the pre-industrial reference period, 1850-1900.
Direct observations that scientists will collect and examine in the coming weeks could soon confirm record warming.
Scientists pointed out that exceeding the two-degree warming standard for at least one day adds a question mark to a series of temperature records recorded in recent months.
Global temperatures set record highs in July, August, September and October. Copernicus Climate Change Service data shows that this trend has continued, if not accelerated, into November.
Even before Saturday, scientists said that 2023 was almost certain to surpass 2016 as the world's hottest year on record, and would likely represent one of the warmest periods in 125,000 years, dating back to a time before Earth's last ice age.
Analyzes released this month show that average global temperatures for 2023 are likely to eventually reach 1.3 to 1.4 degrees Celsius (2.3 to 2.5 Fahrenheit) above pre-industrial levels.
Climate scientists predict that sustained global warming of 1.5 degrees above pre-industrial levels could overwhelm societies and upend economies and political systems.
The planet's temperature rise is only likely to accelerate in the coming months due to the worsening El Niño phenomenon, the notorious climate pattern that leads to extreme weather events and raises global temperatures by releasing massive amounts of heat from the Pacific Ocean into the atmosphere.
But this surge in El Niño-induced warmth typically doesn't come until after the weather pattern has peaked — something that's expected to happen this winter. For this reason, scientists said earlier this year that they do not expect the Earth to reach this record level of warmth until 2024.
Friday's event provides further evidence of how the planet will defy climate scientists' predictions this year.
The United Nations warns of an increase in dust and sand storms in the world
Sand and dust storms remain a problem that does not receive enough attention, even though they have become more widespread today in some areas of the Earth.
The new report of the United Nations Convention to Combat Desertification (UNCCD), published on the organization’s official website, indicates that according to expert assessments, about 2 billion tons of sand and dust are added to the atmosphere every year, which is approximately equivalent to the weight of 350 pyramids the size of the Pyramid of Khufu in Egypt. . Although sand and dust storms are a regional and seasonal phenomenon, their effects are exacerbated by misuse of land and water, as well as droughts and climate change. Practically 25 percent of these storms in the world are linked in one way or another to human activity.
Firas Ziadat, head of the United Nations Convention to Combat Desertification, says: “Sand and dust storms are becoming more frequent and intense, causing significant transboundary impacts and affecting various aspects of the environment, climate, health, agriculture, livelihoods and the social and economic well-being of people. Wherever they arise, they damage agricultural crops, infect livestock and destroy Topsoil in areas of deposition, and atmospheric dust, especially when combined with local industrial pollution, can cause or exacerbate health problems such as respiratory diseases.”
Estimates of the United Nations Convention to Combat Desertification indicate that the world loses about one million square kilometers of agricultural and productive land annually due to desertification. During the years 2015-2019, the area of arable land decreased by 4.2 million square kilometers, which is equivalent to the total territory of the Central Asian countries: Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan.
To combat dust storms, according to experts, it is necessary to restore vegetation and improve land and water management in areas vulnerable to sandstorms.