According to researchers in Biosphere 2, plants can only process up to 600 parts per million of carbon dioxide. Earth is close to 500 parts per million.
In the movie The Martian, based on the fictional novel by Andy Weir, astronaut Mark Watney, the first to walk on the surface of Mars, is stranded on that planet.
With food for a few weeks and facing the possibility that he won’t be rescued for another four years, Mark begins to plant his own food on a planet where nothing has grown before.
The researcher Joaquín Ruiz, from the University of Arizona, says that the story is based on Biosphere 2, where he now works and that it started, precisely, as “science fiction”.
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Biosphere 2 was built in the 1990s, in the desert of Tucson, Arizona and is a large complex of 162,000 square meters. It was created as way to study ecosystems and the levels of pollution that different environments and soils can withstand. This was so that they could recreate the different chemical conditions, for example, of the ocean, rainforest, and the desert.
The latest studies in Biosphere 2 (so called because Earth is considered to be Biosphere 1) show that, unlike previously thought, plants have a limited capacity to absorb carbon dioxide (CO2).
“There has been no experiment of this size or magnitude anywhere else. We increased CO2 concentrations in the jungle from 380 parts per million (ppm) to 820 ppm and we saw the results,” explained the researcher.
According to the data – which has not yet been formally published – in the rainforest ecosystem, where the experiment was conducted, plants can only process up to 600 ppm.
“The most important finding was that the plants could take up to 600 ppm of carbon dioxide in the atmosphere, then they couldn’t take any more, they were neurotic, they could not take more. The argument that CO2 can be taken by plants in infinite forms is not right,” said Joaquín Ruiz.
During a virtual talk organized by the National College entitled “Consequences of climate changes on soils, oceans and rainforests,” the geoscience expert mentioned that when the first investigations of this compound were carried out, it was thought that the plants had unlimited capacity to absorb and turn it into oxygen, but this is not the case.
On May 12, 2019, the Mauna Loa Observatory in Hawaii, which belongs to the Scripps Institute of Oceanography, recorded the highest concentration in all of Earth’s history: 415 ppm, much more than at any point in the past 800,000 years.
According to the United Nations Environment Programme (UNEP), given that Homo sapiens appeared around 300,000 years ago, and the first trace of Homo sapiens sapiens dates back to 196,000 years ago, it can be said that no individual in our species has ever experienced such high levels of CO2.
“This is a major concern regarding our climate and demonstrates, once again, that urgent measures are needed to reduce our greenhouse gas emissions,” said Pascal Peduzzi, Director of UNEP / GRID-Geneva and Program Director of the Global Environment Situation Room, in April this year.
The international organization warned that forest fires, which have increased in probability and severity due to climate change, continue to affect areas of Brazil, Honduras, Myanmar, Thailand and Venezuela, and each of those fires emits large amounts of additional CO2.
Biosphere 2 is composed of seven large structures that look like huge greenhouses. Within each structure, the chemistry of the oceans, rainforests, deserts, and other ecosystems has been recreated to allow for experiments in controlled environments with the minimum conditions of water and oxygen that humanity can survive on.
The first mission came to live in the complex in 1991 and although the psychological effects were more prominent than the environmental ones (because they were isolated for more than two years) Biosphere 2 continues to function and perform experiments on the great social challenges related to water management, environment, and energy through the large-scale design of each of these model ecosystems.
“At the beginning, when it was built, there were eight people who entered to live in it for two and a half years. One of the things that came to light was that psychology is more important than the experiment; after a couple of months of being together, there was a civil war between them. And the two groups that formed made the experiments difficult to finish,” said the scientist.
No other mission was ever isolated again.
Joaquín Ruiz, whose research focuses on paleogeography and environmental and archaeological problems, says that when activities resume in the United States after the period of confinement, the new results on the maximum CO2 conditions that plants can process will be announced in a face-to-face conference.
When questioned about the outlook for ecosystems such as the rainforest, he said that public policies are not on the right track.
“There are two problems to do with the rainforest: one, how fast humans and the public policies they implement can cause geological changes. The changes in Brazil are fatal for the rainforest. The moment you cut down the trees, you not only ruin the rainforest where the highway passes; one of the things that we know about dividing the rainforest in half, is that there is light where there wasn’t before. The changes have been catastrophic in areas where nothing more than a bit of the rainforest was cut down. Studies show that we are on the wrong track. The people are not planting trees where they are going to be used for industry. I don’t see it in a positive way at all.”
The Rainforest Alliance, an organization dedicated to the care of these ecosystems, says in an article published on its website that the only way to combat pandemics and climate change is by taking care of the rainforests.
With a new direction, perhaps we wouldn’t have the need to explore new ways of getting food in places where nothing has ever grown, as with “The Martian”.