Things are not looking good for Earth’s glaciers. Usually, when it comes to climate change and melting ice, we think of the Earth’s polar regions. But they’re not the only important ice formations, and they’re not the only ice that’s melting due to climate change.Continue reading “The World’s Glaciers are Down by 9 Trillion Tonnes of Ice in the Last Half Century”
An international team of scientists have discovered what lay hidden under Arctic ice for thousands or even hundreds of thousands of years. Using data primarily from NASA’s Operation IceBridge, they discovered one of the 25 largest impact craters anywhere on Earth. And its discovery may re-ignite an old climate debate.
That stunning rectangular iceberg that was photographed in mid-October by NASA scientist Jeremy Harbeck had a much more harrowing journey than we thought. Scientists looked back through satellite images to retrace the ‘berg’s journey. They found that it calved from the Larsen C Ice Shelf in November 2017.
Nothing lasts forever, especially an iceberg drifting away from its frigid home. This coffin-shaped iceberg was spotted by astronauts on the International Space Station as it drifted northwards. It split off from a much larger iceberg about 18 years ago, and is moving into warmer and warmer waters.
Arctic sea ice is getting thinner and younger. Satellite data and sonar records from submarines show how the ice coverage in the north is getting more and more seasonal. In the past, ice would build up year over year, getting thicker and stronger. But seasonal ice disappears each summer, meaning more open ocean in the summer, and less of the Sun’s energy being reflected back into space.
Weather tracking is difficult work, and has historically relied on satellites that are large and cost millions of dollars to launch into space. And with the threat of climate change making things like tropical storms, tornadoes and other weather events more violent around the world today, people are increasingly reliant on early warnings and real-time monitoring.
However, NASA is looking to change that by deploying a new breed of weather satellite that takes advantage of recent advances in miniaturization. This class of satellite is known as the RainCube (Radar in CubeSat), which uses experimental technology to see storms by detecting rain and snow using very small and sophisticated instruments.
Even if you know nothing about hurricanes, an unavoidable sense of doom and destruction overtakes you when you look at this image of Hurricane Florence as it moves inexorably toward North and South Carolina.
Even if you didn’t know that the powerful storm is forecast to gain strength as it hits the coast on Friday, or that it will dump several months of rain onto the region in a mere few days, or that the storm surge could reach as high as 9 to 13 ft. If you didn’t know all those things, the picture of Florence taken from space would still fill you with foreboding.
Stand outside and take deep breath. Do you know what you’re breathing? For most people, the answer is simple – air. And air, which is essential to life as we know it, is composed of roughly twenty-percent oxygen gas (O²) and seventy-eight percent nitrogen gas (N²). However, within the remaining one-percent and change are several other trace gases, as well as few other ingredients that are not always healthy.
NASA’s Earth Observatory is a vital part of the space agency’s mission to advance our understanding of Earth, its climate, and the ways in which it is similar and different from the other Solar Planets. For decades, the EO has been monitoring Earth from space in order to map it’s surface, track it’s weather patterns, measure changes in our environment, and monitor major geological events.
For instance, Mount Sinabung – a stratovolcano located on the island of Sumatra in Indonesia – became sporadically active in 2010 after centuries of being dormant. But on February 19th, 2018, it erupted violently, spewing ash at least 5 to 7 kilometers (16,000 to 23,000 feet) into the air over Indonesia. Just a few hours later, Terra and other NASA Earth Observatory satellites captured the eruption from orbit.
The images were taken with Terra’s Moderate Resolution Imaging Spectroradiometer (MODIS), which recorded a natural-color image of the eruption at 11:10 am local time (04:10 Universal Time). This was just hours after the eruption began and managed to illustrate what was being reported by sources on the ground. According to multiple reports from the Associated Press, the scene was one of carnage.
According to eye-witness accounts, the erupting lava dome obliterated a chunk of the peak as it erupted. This was followed by plumes of hot gas and ash riding down the volcano’s summit and spreading out in a 5-kilometer (3 mile) diameter. Ash falls were widespread, covering entire villages in the area and leading to airline pilots being issued the highest of alerts for the region.
In fact, ash falls were recorded as far as away as the town of Lhokseumawe – located some 260 km (160 mi) to the north. To address the threat to public health, the Indonesian government advised people to stay indoors due to poor air quality, and officials were dispatched to Sumatra to hand out face masks. Due to its composition and its particulate nature, volcanic ash is a severe health hazard.
On the one hand, it contains sulfur dioxide (SO²), which can irritate the human nose and throat when inhaled. The gas also reacts with water vapor in the atmosphere to produce acid rain, causing damage to vegetation and drinking water. It can also react with other gases in the atmosphere to form aerosol particles that can create thick hazes and even lead to global cooling.
These levels were recorded by the Suomi-NPP satellite using its Ozone Mapper Profiler Suite (OMPS). The image below shows what SO² concentrations were like at 1:20 p.m. local time (06:20 Universal Time) on February 19th, several hours after the eruption. The maximum concentrations of SO² reached 140 Dobson Units in the immediate vicinity of the mountain.
Erik Klemetti, a volcanologist, was on hand to witness the event. As he explained in an article for Discovery Magazine:
“On February 19, 2018, the volcano decided to change its tune and unleashed a massive explosion that potentially reached at least 23,000 and possibly to up 55,000 feet (~16.5 kilometers), making it the largest eruption since the volcano became active again in 2013.”
Klemetti also cited a report that was recently filed by the Darwin Volcanic Ash Advisory Center – part of the Australian Government’s Bureau of Meteorology. According to this report, the ash will drift to the west and fall into the Indian Ocean, rather than continuing to rain down on Sumatra. Other sensors on NASA satellites have also been monitoring Mount Sinabung since its erupted.
This includes the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), an environmental satellite operated jointly by NASA and France’s Centre National d’Etudes Spatiales (CNES). Data from this satellite indicated that some debris and gas released by the eruption has risen as high as 15 to 18 km (mi) into the atmosphere.
In addition, data from the Aura satellite‘s Ozone Monitoring Instrument (OMI) recently indicated rising levels of SO² around Sinabung, which could mean that fresh magma is approaching the surface. As i concluded:
“This could just be a one-off blast from the volcano and it will return to its previous level of activity, but it is startling to say the least. Sinabung is still a massive humanitarian crisis, with tens of thousands of people unable to return to their homes for years. Some towns have even been rebuilt further from the volcano as it has shown no signs of ending this eruptive period.”
Be sure to check out this video of the eruption, courtesy of New Zealand Volcanologist Dr. Janine Krippner:
Further Reading: NASA Earth Observatory
One of the most visible signs of Climate Change are the ways in which glaciers and ice sheets have been disappearing all over the world. This trend is not reserved to the Arctic ice cap or the Antarctic Basin, of course. On every part of the planet, scientists have been monitoring glaciers that have been shrinking in the past few decades to determine their rate of loss.
These activities are overseen by NASA’s Earth Observatory, which relies on instruments like the Landsat satellites to monitor seasonal ice losses from orbit. As these satellites demonstrated with a series of recently released images, the Puncak Jaya ice sheets on the south pacific island of Papua/New Guinea have been receding in the past three decades, and are at risk of disappearing in just a decade.
The Papau province of New Guinea has a very rugged landscape that consists of the mountains that make up Sudirman Range. The tallest peaks in this range are Puncak Jaya and Ngga Pulu, which stand 4,884 meters (16,020 feet) and 4,862 meters (15,950 feet) above sea level, respectively. Despite being located in the tropics, the natural elevation of these peaks allows them to sustain small fields of “permanent” ice.
Given the geography, these ice fields are incredibly rare. In fact, within the tropics, the closest glacial ice is found 11,200 km (6,900 mi) away on Mount Kenya in Africa. Otherwise, one has to venture north for about 4,500 km (2,800 mi) to Mount Tate in central Japan, where glacial ice is more common since it is much farther away from the equator.
Sadly, these rare glaciers are becoming more threatened with every passing year. Like all tropical glaciers in the world today, the glaciers on the slopes around Puncak Jaya have been shrinking at a such a rate that scientists estimate that they could be gone within a decade. This was illustrated by a pair of Landsat images that show how the ice fields have shrunk over the past thirty years.
The first of these images (shown above) was acquired on November 3rd, 1988, by the Thematic Mapper instrument aboard the Landsat 5 satellite. The second image (shown below) was acquired on December 5th, 2017, by the Operational Land Imager (OLI) on the Landsat 8 satellite. These false-color images are a combination of shortwave infrared, infrared, near-infrared, and red light.
The extent of the ice fields are shown in light blue, whereas rocky areas are represented in brown, vegetation in green, and clouds in white. The gray circular area near the center of the 2017 image is the Grasberg mine, the largest gold and second-largest copper mine in the world. This mine expanded considerably between the 1980s and 2000s are a result of a boom in copper prices.
As the images show, in 1988, there were five masses of ice resting on the mountain slopes – the Meren, Southwall, Carstensz, East Northwall Firn and West Northwall Firn glaciers. However, by 2017, only the Carstensz and a small portion of the East Northwall Firn glaciers remained. As Christopher Shuman, a research professor at the University of Maryland Baltimore County and NASA’s Goddard Space Flight Center, explained:
“The ice area losses since the 1980s here are quite striking, visible in the contrast of the blue ice with the reddish bedrock. Even though the area still gets snowfalls, it is clearly not sustaining these glacial remnants.”
Similarly, in 2009, images taken by Landsat 5 of these same glaciers (see below) indicated that the Meren and Southwall glaciers had disappeared. Meanwhile, the Carstensz, East Northwall Firn and West Northwall Firn glaciers had retreated dramatically. Based on the rate of loss, scientists estimated at the time that all of Puncak Jaya’s glaciers would be gone within 20 years.
As these latest images demonstrate, their estimates were right on the money. At their current rate, what remains of the Carstensz and East Northwall Firn glaciers will be gone by the late 2020s. The primary cause of the ice loss is rising air temperatures, which leads to rapid sublimation. However, changes in humidity levels, precipitation patterns and cloudiness can also have an impact.
Humidity is also important, since it affects how readily glaciers can lose mass directly to the atmosphere. Where the air is more moist, ice is able to make the transition to water more easily, and can be returned to the glacier in the form of precipitation. Where the air is predominately dry, ice makes the transition directly from a solid form to a gaseous form (aka. sublimation).
Temperature and precipitation are also closely linked to ice loss. Where temperatures are low enough, precipitation takes the form of snow, which can sustain glaciers and cause them to grow. Rainfall, on the other hand, will cause ice sheets to melt and recede. And of course, clouds affect how much sunlight reaches the glacier’s surface, which results in warming and sublimation.
For many tropical glaciers, scientists are still working out the relative importance of these factors and attempting to determine to what extent anthropogenic factors plays a role. In the meantime, tracking how these changes are leading to ice loss in the tropical regions provides scientists with a means of comparison when studying ice loss in other parts of the world.
As Andrew Klein, a geography professor at Texas A & M University who has studied the region, explained:
“Glacier recession continues in the tropics—these happen to be the last glaciers in the eastern tropics. Fortunately, the impact will be limited given their small size and the fact that they do not represent a significant water resource.”
Satellites continue to play an important role in the monitoring process, giving scientist the ability to map glacier ice loss, map seasonal changes, and draw comparisons between different parts on the planet. They also allow scientists to monitor remote and inaccessible areas of the planet to see how they too are being affected. Last, but not least, they allow scientists to estimate the timing of a glacier’s disappearance.
Further Reading: NASA Earth Observatory