Tag Archives: climate

Climate Change’s Impact on Deep Sea Ecosystems

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New research reveals that fire ice, or frozen methane, trapped as a solid under the oceans is at risk of melting due to climate change, potentially releasing large amounts of methane into the atmosphere. I did. Using advanced seismic imaging, the research team found that dissociated methane can travel significant distances, overturning previous assumptions about its stability.

Research shows that ocean fire ice, or frozen methane, is more likely to melt due to climate change and poses a significant threat to methane emissions into the atmosphere.

An international research team led by the University of Newcastle has discovered that when frozen methane and ice melt, the powerful greenhouse gas methane is released and travels from the deepest parts of continental slopes to the edges of underwater shelves. They also found a pocket that had traveled 25 miles (40 kilometers).

Publication in magazine natural earth scienceresearchers say this means more methane could potentially become vulnerable and released into the atmosphere as a result of climate warming.

Methane hydrate: the hidden climate change threat

Methane hydrate, also known as fire ice, is an ice-like structure containing methane buried under the ocean. Huge amounts of methane are stored in the ocean as marine methane. As the ocean warms, it melts, releasing methane, known as dissociated methane, into the ocean and atmosphere, contributing to global warming.

The researchers used advanced three-dimensional seismic imaging techniques to examine sections of hydrate that have dissociated during climate warming off the coast of Mauritania in northwest Africa. They identified specific cases where dissociated methane traveled more than 40 kilometers and was released through underwater depressions known as pockmarks during warm periods in the past.

Researchers at Newcastle University have found that frozen methane trapped on the ocean floor is more likely to melt due to climate change and could be released into the ocean.Credit: Newcastle University

Discovery and its impact

Professor Richard Davies, lead author and Vice-Chancellor for Global and Sustainability at Newcastle University, said: . Our study shows that they formed as methane released from hydrates from the deepest parts of the continental slope spewed into the ocean. Scientists previously thought these hydrates would be less susceptible to climate warming, but it turns out some are more susceptible. ”

Researchers have previously studied how changes in seafloor temperatures near continental margins affect methane release from hydrates. However, these studies mainly focused on regions where only a small fraction of the earth’s methane hydrate exists. This is one of the few studies to investigate methane emissions from the bottom of hydrate stability zones deep underwater. The results show that the methane released from the hydrate stability zone migrated a significant distance towards land.

Broader research perspective and future plans

Professor Christian Berndt, Head of the Ocean Geodynamics Research Unit at GEOMAR in Kiel, Germany, added:

“This is an important finding. Previous research efforts have focused on the shallowest part of the hydrate stability zone, because we thought this was the only part that would be susceptible to climate change.

“New data clearly shows that far greater amounts of methane can be released from ocean hydrates, and a thorough understanding of this fact is needed to better understand the role of hydrates in the climate system. need to be clarified.”

Methane is the second most common anthropogenic greenhouse gas after carbon dioxide (CO2). Methane accounts for about 16% of global greenhouse gas emissions, according to U.S. Environmental Protection Agency figures.

The findings could play an important role in predicting and addressing methane’s impact on a changing climate.

The researchers plan to continue looking for evidence of methane vents along the margin and predict where large methane seeps may occur as the planet warms. Researchers are now planning a scientific expedition to examine the pockmarks more closely and see if they can be more closely linked to past climate warming events.

Reference: “Long-distance transport and emissions of methane from the base of the hydrate stability zone” Richard J. Davies, Jinxiu Yang, Mark T. Ireland, Christian Berndt, Miguel Ángel Morales Maqueda, Mads Huuse, December 6, 2023 , natural earth science.
DOI: 10.1038/s41561-023-01333-w

Source: scitechdaily.com

New findings on ancient climate analysis suggest that CO2 is contributing to more warming than previously believed

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A diagram of Earth 65 million years ago, when CO2 levels were much higher than today.

Chris Butler/Science Photo Library

Perhaps the most difficult question in climate science. That is, how much global warming does carbon dioxide cause? A new analysis of 66 million years of Earth’s climate history suggests that the Earth is far more sensitive to greenhouse gases than current climate models predict, which could lead to even warmer temperatures in the long term. This means that there is a possibility of further development.

A key factor determining the impact of our emissions on the planet is how much the planet warms in response to the extra CO2 we pump into the atmosphere. This sensitivity is affected by various feedback loops related to clouds, melting ice sheets, and other influences.

One way to measure this sensitivity is to look at how the climate has changed in the past. Gases trapped in ice cores can only take us back about 800,000 years, so to go even further back in time to look at temperatures and CO2 levels in the atmosphere, researchers used proxies. Masu. For example, the density of pores in plant leaves and the isotope levels in the fossil shells of marine organisms change in response to CO2 levels.

However, discrepancies between different proxies have led to an uncertain view of Earth’s ancient climate. Now, an extensive review by a team of over 80 researchers provides a clearer picture. More accurate representation of ancient CO2 levels. “We now have a much clearer picture of what carbon dioxide levels have been in the past,” he says. Berber Henisch He coordinated the project at Columbia University in New York.

This allows us to understand current CO2 levels in the atmosphere alongside the deep past. This indicates that the last time CO2 levels were as consistently high as they are now was about 14 million years ago, and much earlier than that. previous estimate.

By comparing this new CO2 data with temperature records, “we can learn how sensitive the climate has been to changes in carbon dioxide,” Hoenisch says. Current climate models estimate that doubling his CO2 levels in the atmosphere would result in a warming of 1.5°C to 4.5°C. However, the results suggest that the temperature increase is even larger, between 5°C and 8°C.

However, there is a big caveat. This new insight into the history of Earth’s deep climate covers trends over hundreds of thousands of years, rather than the short timescales of decades or centuries that are relevant to humanity today, and therefore It doesn’t tell you what the temperature is likely to be. “It’s a slow cascading effect that slowly kicks in,” Hoenisch says.

The vast time scales covered in this study also mean that details of climate sensitivity cannot be detected. michael man Researchers at the University of Pennsylvania say climate sensitivities may have been different at other times in Earth’s history compared to today, which is likely why the study yielded higher estimates than those based on more recent periods. I think this explains why I got there.

“The bottom line is that the climate sensitivity estimates from this study probably don’t apply to current anthropogenic warming,” Mann says. “Nonetheless, this study confirms a very close relationship between CO2 and global temperatures, highlighting the continuing threat of fossil fuel combustion.”

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Source: www.newscientist.com

The Surprising Role of NASA in Tackling the Climate Crisis

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Flaring, the deliberate burning of excess natural gas into the atmosphere, is one way methane is released from oil and gas facilities. His EMIT mission for NASA, over more than a year of operation, demonstrated its proficiency in discovering methane and other greenhouse gas emissions from space.

Since its launch 16 months ago, the EMIT imaging spectrometer has international space station demonstrated the ability to detect more than just surface minerals. More than a year after first detecting a methane plume from its perch on the International Space Station (ISS), data from NASA’s EMIT instrument is now being used to analyze greenhouse gas emissions with a level of proficiency that surprised even its designers. used to identify source emissions.

EMIT‘s mission and capabilities

EMIT, which stands for Earth Surface Mineral Dust Source Investigation, was launched in July 2022 to map 10 major minerals on the surface of the world’s arid regions. Mineral-related observations are already available. researcher and the general public to better understand how dust in the atmosphere affects the climate.

Methane detection was not part of EMIT‘s primary mission, but the instrument’s designers expected the imaging spectrometer to have that capability. More than 750 sources of emissions have been identified since August 2022, some of which are small, located in remote areas, and persistent over long periods of time, according to a new study published in the journal However, this device is said to have achieved more than sufficient results in that respect. scientific progress.

EMIT identified a cluster of 12 methane plumes within a 150 square mile (400 square kilometer) area in southern Uzbekistan on September 1, 2022. The instrument captured this cluster, which the researchers call a “scene,” in a single shot.

Credit: NASA/JPL-California Institute of Technology

Methane emissions and climate change

“We were a little cautious at first about what this device could do,” said Andrew Thorpe, a research engineer on the EMIT science team. NASAis a researcher at the Jet Propulsion Laboratory in Southern California and the paper’s lead author. “It exceeded our expectations.”

Knowing where methane emissions are coming from gives operators of landfills, agricultural sites, oil and gas facilities, and other methane-producing facilities the opportunity to address methane emissions. Tracking human methane emissions is key to limiting climate change because it provides a relatively low-cost and rapid approach to reducing greenhouse gases. Methane remains in the atmosphere for about 10 years, during which time it traps heat up to 80 times more strongly than carbon dioxide, which remains for centuries.

When strong winds kick up mineral rock dust(such as calcite or chlorite) on one continent, the airborne particles can travel thousands of miles and impact an entirely different continent. Airborne dust can heat or cool the atmosphere and the ground. This heating or cooling effect is the focus of NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) mission.

Credit: NASA/JPL-California Institute of Technology

amazing results

EMIT has proven effective in detecting both large-scale sources (tens of thousands of pounds of methane per hour) and surprisingly small sources (hundreds of pounds of methane per hour). It has been. This is important because it will allow us to identify more “superemitters,” or sources that produce a disproportionate share of total emissions.

A new study documents how EMIT was able to observe 60% to 85% of the methane plumes typically seen during airborne operations, based on the first 30 days of greenhouse gas detections.

On September 3, 2022, EMIT detected a methane plume emitting approximately 979 pounds (444 kilograms) per hour in a remote corner of southeastern Libya. This is one of the smallest sources ever detected by this instrument.

Credit: NASA/JPL-California Institute of Technology

Comparison with airborne detection

From thousands of feet above the ground, an aircraft’s methane detection equipment is more sensitive, but researchers need advance notice that they will detect methane before the aircraft can be dispatched. Many areas are not explored because they are considered too remote, too dangerous, or too expensive. Furthermore, actual campaigns cover a relatively limited area over a short period of time.

EMIT, on the other hand, will collect data from a space station at an altitude of about 400 kilometers, covering a wide area of ​​the Earth, especially the arid region between 51.6 degrees north and 51.6 degrees south latitude. The imaging spectrometer produces a 50-mile-by-50-mile (80-kilometer-by-80-kilometer) image of the Earth’s surface (researchers call it a “scene”), including many areas that could not be reached with airborne instruments. capture.

“The number and size of methane plumes that EMIT has measured around our planet is astonishing,” said Robert O. Green. JPL Senior Researcher and Principal Investigator at EMIT.

NASA EMIT

We created this time-lapse video showing the International Space Station’s Canadarm2 robotic arm moving NASA’s EMIT mission outside the station. The Dragon spacecraft was launched…

Posted by NASA EMIT on Wednesday, October 26, 2022

Detection by scene

To help identify sources, the EMIT science team created maps of methane plumes and identified them as Websitethe underlying data are available at the NASA and U.S. Geological Survey Joint Land Processes Distributed Active Archive Center (LPDAAC). Data from this mission will be available to the public, scientists, and organizations.

EMIT began collecting observations in August 2022 and has since recorded more than 50,000 scenes. The instrument discovered clusters of emission sources in little-studied areas. Southern Uzbekistan On September 1, 2022, we detected 12 methane plumes totaling approximately 49,734 pounds (22,559 kilograms) per hour.

Additionally, the instrument detected a much smaller plume than expected.captured in a secluded corner Southeastern Libya On September 3, 2022, one of the smallest sources to date was emitting 979 pounds (444 kilograms) per hour, based on local wind speed estimates.

Reference: “Attribution of Individual Methane and Carbon Dioxide Sources Using EMIT Observations from Space” Andrew K. Thorpe, Robert O. Green, David R. Thompson, Philip G. Brodrick, John W. Chapman, Clayton D. Elder, Itziar, Iraklis-Leuchert, Daniel H. Cusworth, Alana K. Ayasse, Riley M. Duren, Christian Frankenberg, Louis Gunter, John R. Warden, Philip.・E. Dennison, Dar A. Roberts, K. Dana Chadwick, Michael L. Eastwood, Jay E. Farren and Charles E. Miller, November 17, 2023, scientific progress.

DOI: 10.1126/sciadv.adh2391

EMIT mission details

EMIT was selected from the Earth Venture Instrument-4 public offering by NASA’s Science Mission Directorate’s Earth Sciences Division and was developed at NASA’s Jet Propulsion Laboratory, managed for NASA by the California Institute of Technology in Pasadena, California. Data from this instrument is publicly available for use by other researchers and the public at the NASA Land Processes Distributed Active Archive Center.

Source: scitechdaily.com