Tag Archives: greenhouse

Ancient Volcanoes: Understanding Low Greenhouse Gas Emissions in Earth’s History

Posted on by
Reply

Arc volcanoes like Sakurajima releasing carbon dioxide

Arc-shaped volcanoes like Japan’s Sakurajima release carbon dioxide from the Earth’s interior

Asahi Shimbun via Getty Images

New research suggests that the impact of volcanoes on Earth’s climate may not be as ancient as previously believed.

The Earth’s climate has experienced shifts between “icehouse” and “greenhouse” conditions, largely dictated by greenhouse gas levels like carbon dioxide.

Volcanic arcs, including significant eruptions from mountain ranges such as Japan’s, release CO2 from deep within the Earth. Recent findings indicate that dinosaurs became a substantial source of carbon emissions only towards the end of their reign, approximately 100 million years ago, according to Ben Mather and his team from the University of Melbourne.

This correlates with the emergence of phytoplankton featuring calcium carbonate scales in the oceans approximately 150 million years ago. When these organisms perish, they deposit large amounts of calcium carbonate on the ocean floor.

As tectonic plates shift, these significant reservoirs of carbon are pushed into the mantle and recycled into the Earth’s molten core via a process known as subduction.

“Most of the carbon derived from plankton on the subducting oceanic plate mixes into the melt interior, but a portion is released through volcanic arcs,” explains Mather.

Before the emergence of scaly plankton, volcanic arc emissions contained relatively lower levels of CO2, according to Mather.

Through modeling, Mather and colleagues examined tectonics’ long-term impact on the carbon cycle over the past 500 million years. They discovered that much of the carbon stored within Earth throughout its history was released through crustal fractures in a process termed rifting, not primarily through volcanic arcs.

Rifting, a geological process where continents separate, can occur on land (as in the East African Rift) or along mid-ocean ridges.

“As tectonic plates separate, they effectively ‘roof off’ parts of the molten Earth,” Mather states. “This process generates new crust at mid-ocean ridges, releasing carbon.” The amount of carbon entering the atmosphere from continental fractures and mid-ocean ridges relies on the cracks’ length and the rate at which they separate, a process that has remained relatively stable. However, emissions from volcanic arcs have surged in the last 100 million years due to new carbon reservoirs formed by plankton.

Currently, Earth is in a temporary warm phase called an interglacial period, nested within a larger ice age that began 34 million years ago. One reason for the persistent cold phases is that phytoplankton sequester substantial amounts of carbon from the ocean, depositing it on the sea floor. Although volcanic emissions are rising, they still pale in comparison to the carbon stored by phytoplankton and that sequestered through tectonic movements.

According to Alan Collins and his team from the University of Adelaide, modeling studies like this are crucial for comprehending how volcanic and tectonic activities have influenced climate patterns over geological timescales.

“The composition of marine sediments has shifted as new organisms evolved, utilizing diverse elements, including the rise of calcium carbonate-based zooplankton,” Collins emphasizes.

Reference journal: Nature Communications Earth and Environment, DOI TK

Explore the Land of Fire and Ice: Iceland

Embark on an unforgettable journey through Iceland’s breathtaking landscapes. Experience volcanic and geological marvels by day, and chase the mesmerizing Northern Lights by night (October).

Topic:

This revision enhances SEO through keywords and improves readability while retaining the HTML structure.

Source: www.newscientist.com

How Ancient Mass Extinctions Revealed Earth’s Evolution into a Super Greenhouse

Posted on by
Reply

Here’s a rewritten version of the provided content while retaining the HTML tags:

Current forest die-offs due to global warming resemble those from the Permian and Triassic extinction events.

Ina Fassbender/AFP via Getty Images

Following a dramatic increase in carbon dioxide levels 252 million years ago, the death of forests resulted in enduring climate alterations, with the greenhouse effect persisting for millions of years.

Researchers striving to comprehend this phenomenon, which triggered the largest mass extinction in Earth’s history, caution that ongoing greenhouse gas emissions may lead to similar outcomes.

The extinction events of the Permian and Triassic are believed to have been triggered by extensive volcanic activity in what is now Siberia, elevating atmospheric CO2 concentrations.

The planet’s surface temperature soared by as much as 10°C, with average temperatures in the equatorial regions climbing to 34°C (93°F)—a rise of 8°C above the current average.

These extreme conditions persisted for roughly 5 million years, causing over 80% of marine species and upwards of 70% of terrestrial vertebrate families to become extinct, according to some estimates.

Although some scientists have recently posited that these mass extinction events may have limited effects on terrestrial ecosystems, Andrew Meldis from the University of Adelaide expresses confidence that life was nearly extinguished 252 million years ago.

“Small pockets of life might survive mass extinctions in isolated enclaves, but many areas within the Permian-Triassic fossil record reveal a complete ecosystem collapse,” notes Meldis.

He and his team scrutinized the fossil record to investigate why the Super Greenhouse event, which drives mass extinction, lasted five million years—far longer than the 100,000 years predicted by climate models.

The findings revealed that vast expanses of forests, originally with canopies of around 50 meters, were supplanted by resilient underground flora, typically ranging from 5 cm to 2 meters in height. Additionally, peat marshes, significant carbon storage ecosystems, vanished from tropical areas.

Employing computer models of Earth’s climatic and geochemical systems, researchers indicated that the depletion of these ecosystems contributes to elevated CO2 levels persisting for millions of years. This predominantly occurs because vegetation plays a crucial role in weathering, the mechanism that extracts carbon from the atmosphere and sequesters it in rocks and soil over extensive timescales.

With atmospheric CO2 levels rising rapidly, the parallels to the present are striking, asserts Meldis. As temperatures escalate, tropical and subtropical forests may find it increasingly challenging to adapt, potentially surpassing thresholds where vegetation ceases to maintain climate equilibrium.

Meldis explains that simply restoring former ecosystems will not lead to a “ping-pong effect.” He emphasizes that the atmosphere cannot be swiftly rejuvenated after the loss of the equatorial forest.

“You’re not transitioning from an ice house to a greenhouse and then back; the Earth will find a new equilibrium, which may differ significantly from prior states,” he elaborates.

Catlin Maisner, a researcher at the University of New South Wales—who was not involved in the study—describes reconstructing these events as analogous to “trying to assemble a jigsaw puzzle with many missing pieces,” yet acknowledges the team’s arguments as “plausible.”

However, she notes considerable uncertainty regarding oceanic processes during this period. “The ocean harbors far more carbon than land and atmosphere combined, and we still lack a comprehensive understanding of how marine biology, chemistry, and physical circulation were affected during that event,” cautions Meissner.

Topics:

  • Climate change/
  • Paleontology

Feel free to adjust any sections as needed!

Source: www.newscientist.com

The Earth’s Sensitivity to Greenhouse Gases is Greater Than We Realized

Posted on by
Reply

Climate change might be even more severe than previously estimated

kapook2981/getty images

The Earth’s climate appears to be more responsive to the pollution caused by greenhouse gases than previously assumed, making it harder to keep global temperature increases below 2°C.

This is concerning news for global efforts to combat climate change, according to Gunnar Myhre from Cicero International Climate Research Centre in Norway.

Researchers have long been aware that releasing greenhouse gases into the atmosphere can lead to climate warming with widespread consequences. However, the extent of potential warming due to these emissions remains uncertain. Specifically, how sensitive is the Earth’s climate to this pollution?

The primary uncertainty arises from how clouds react to warming atmospheres, as shifts in cloud systems could exacerbate warming through feedback loops.

Most predictions regarding warming by the century’s end are derived from climate models that incorporate various sensitivity assumptions. The model utilized by the Intergovernmental Panel on Climate Change indicates that if atmospheric concentrations double compared to pre-industrial levels, warming could range between 2°C and 5°C, prompting organizations to adopt a median estimate of 3°C.

Myhre and his team sought to align climate model predictions with satellite data showing the Earth’s energy imbalance—a measure of excess heat within our climate system, reflecting its sensitivity levels.

They discovered that less sensitive climate models, which suggest that the Earth’s climate is more resistant to greenhouse gas emissions, did not align with satellite data collected since the turn of the millennium. According to Myhre, models asserting that the Earth’s climate is less resistant to these gases are “more common.” He added, “Models predicting minimal warming are increasingly rare.”

The findings challenge the reliability of climate models forecasting warming below 2.9°C with doubled greenhouse gas concentrations. Instead, the data imply that warming beyond this threshold is more probable for the same level of pollution.

This has been corroborated by recent record-high temperatures observed both on land and in the sea since 2023, described as “strong climate feedback” in the atmosphere by Myhre.

A more sensitive climate necessitates a quicker reduction in emissions to maintain the same temperature trajectory. In essence, the world must accelerate decarbonization efforts to meet its climate commitments.

Johannes Kuas from the University of Leipzig in Germany argues that the study presents a “very plausible contention” that the Earth is indeed more sensitive to global warming than some models suggest, stating it “reduces the margin” for model estimations that scientists should follow. “It highlights the urgent need for political action against climate change,” he emphasized.

Richard Allen from the University of Reading in the UK notes that “natural climate change” could also be part of the narrative, by pointing out that satellite records date back only to 2001. Nevertheless, he describes the study as “rigorous” and adds, “there is further evidence that simulations predicting less warming are increasingly unrealistic in the long-term.”

topic:

Source: www.newscientist.com

Astrobiologists pinpoint five key greenhouse gases found on terraformed exoplanets

Posted on by
Reply

The five man-made greenhouse gases identified by astrobiologist Edward Schwieterman of the University of California, Riverside, and his colleagues could be detected in relatively low concentrations in exoplanet atmospheres using the NASA/ESA/CSA James Webb Space Telescope and future space telescopes.

Diagram of the technological features of various planets, including artificial atmospheric gases. Image courtesy of Sohail Wasif / University of California, Riverside.

“For us, these gases are bad because we don’t want them to accelerate warming,” Dr Schwietermann said.

“But they could be useful to a civilization wanting to halt an impending ice age, or to terraform uninhabitable planets in its own system, as humanity has proposed for Mars.”

“These gases are not known to occur in large quantities in nature, so they have to be manufactured.”

“Finding them would therefore be evidence of the presence of intelligent, technological life forms. Such evidence is called a technosignature.”

The five gases proposed by the authors are used on Earth for industrial purposes, such as making computer chips.

These include fluorinated versions of methane, ethane and propane, as well as gases made of nitrogen and fluorine, or sulfur and fluorine.

One advantage is that it’s a very effective greenhouse gas — sulfur hexafluoride, for example, has a warming power 23,500 times that of carbon dioxide — and even a relatively small amount could heat a frozen planet to the point where liquid water could remain on the surface.

Another advantage of the proposed gas, at least from an alien perspective, is that it is extremely long-lived, surviving in an Earth-like atmosphere for up to 50,000 years.

“You won’t need to refill it very often to maintain a comfortable climate,” Dr. Schwieterman said.

Others suggest that refrigerant chemicals such as CFCs are technology signature gases because they are almost entirely man-made and visible in Earth’s atmosphere.

But unlike the chemically inert fully fluorinated gases discussed in the new paper, CFCs damage the ozone layer and may not be advantageous.

“If other civilizations had oxygen-rich atmospheres, they would have also had an ozone layer that they wanted to protect,” Dr Schwietermann said.

“CFCs will be broken down in the ozone layer while also catalyzing its destruction.”

“CFCs degrade easily and have a short lifespan, making them difficult to detect.”

Finally, for fluorinated gases to have an effect on climate, they need to absorb infrared radiation.

This absorption creates an infrared signature that can be detected by space telescopes.

Using current and planned technology, scientists may be able to detect these chemicals in nearby exoplanetary systems.

“In an Earth-like atmosphere, only one in a million molecules could be any of these gases and be detectable, and that concentration would be enough to even alter the climate,” Dr Schwietermann said.

To reach this calculation, the astrobiologists simulated a planet in the TRAPPIST-1 system, located about 40 light-years from Earth.

They chose this system because it contains at least seven rocky planets and is one of the best-studied planetary systems other than Earth.

Although it is not possible to quantify the likelihood of discovering man-made greenhouse gases in the near future, we are confident that, if they exist, they could be detected during missions currently planned to characterize the planet’s atmosphere.

“If telescopes are already characterizing planets for other reasons, there would be no need for extra effort to look for these technical features,” Dr Schwietermann said.

“And when you find them, it’s amazing.”

Team work Published in Astrophysical Journal.

_____

Edward W. Schwietermann others2024. Artificial greenhouse gases as a technological feature of exoplanets. ApJ 969, 20; doi: 10.3847/1538-4357/ad4ce8

Source: www.sci.news

New Satellite Launched to Monitor Emissions of Potent Greenhouse Gases

Posted on by
Reply

MethaneSAT artist impressions

Environmental Defense Fund/NASA

A satellite that is expected to change the way we look at global warming methane emissions from oil and gas production has launched from California's Vandenberg Space Force Base. The satellite, called MethaneSAT, will orbit the Earth 15 times a day and use infrared sensors to measure methane leaking from all the world's major production centers.

“We specifically designed MethaneSAT to accomplish one goal,” he says. stephen hamburger The Environmental Defense Fund (EDF) is a nonprofit advocacy group that developed the satellite with a consortium of universities and aerospace companies. “To generate policy-relevant data to track methane emissions from the oil and gas industry around the world.”

Methane is the most important greenhouse gas after carbon dioxide. And oil, gas and coal production are among the largest sources of anthropogenic methane emissions. Many governments have set targets to reduce methane emissions by 30 percent by 2030, and at last year's COP28 climate change summit, many major oil and gas companies announced plans to reduce methane emissions by 30 percent by 2050. It pledged to reduce methane emissions to zero..

However, it is difficult to assess progress against these commitments. Current methane emissions remain poorly quantified, leaks are difficult to track, and aerial surveys and ground monitoring are expensive and some countries do not allow them. MethaneSAT joins a growing family of methane detection instruments in orbit, aiming to provide better visibility. Existing satellites, such as the European Space Agency's TROPOMI, detect methane emissions over large areas. Other devices, like the 11 methane detection devices operated by Canadian company GHGSat, focus on identifying specific point sources of methane.

In contrast, MethaneSAT regularly monitors methane at high resolution between these scales, allowing researchers to quantify emissions across regions associated with oil and gas production and identify possible sources. can be mapped. “We needed to be able to see all the emissions and resolve them in space,” Hamburg says.

When fully operational, the satellite will deliver up to 30 different “scenes” measuring methane fluxes over 40,000 square kilometers per day, according to the City of Hamburg. He said he will prioritize monitoring oil and gas producing regions such as the Permian Basin in West Texas, but will also be able to measure methane from other major sources such as agriculture, wetlands and landfills. “Methane is methane,” he says.

In parallel with the development of the satellite, Hamburg et al. are building a pipeline to rapidly convert the raw data it generates into publicly available estimates of methane emissions and the likely sources of plumes. was built. This includes a global database of oil and gas infrastructure. Created in partnership with Google Helps connect methane detection to its source.

“We're mapping the whole thing,” Hamburg says. He said the satellite will generate more data on methane emissions from oil and gas in its first year of operation than has been collected in the past 50 years. Full data collection is expected to begin in early 2025.

“The data is here and the technology is here to initiate action,” he says. Jean-François Gauthier GHGSat's hope is that MethaneSAT will help identify sources of emissions, allowing GHGSat's focused satellites to measure in more detail.

rob jackson Stanford University in California says the satellite can independently check emissions reported by companies and countries. “There will be nowhere to hide,” he says. The flood of data may also help explain the still-uncertain causes of the rise in methane rates since 2007, he added.

“The big question for me is how do people use that information,” Jackson says. “There's an assumption that if we had all the information, the emissions would somehow go away. But having information from aircraft and ground sources didn't stop these emissions.”

topic:

Source: www.newscientist.com

Greenhouse Gas Emissions Expected to Decrease Starting in 2024

Posted on by
Reply

Carbon emissions from fossil fuels could finally start declining in 2024

Villanor/Shutterstock

Emissions of greenhouse gases that cause global warming have been on the rise since the Industrial Revolution, and 2023 looks set to be no different. According to him, this year emissions from fossil fuel combustion increased by more than 1% compared to 2022. global carbon budget Edited by Pierre Friedlingstein and his colleagues from the University of Exeter, UK.

However, in 2024, these emissions could begin to decline for the first time, largely due to unprecedented circumstances.

Source: www.newscientist.com