Global glacier retreat has accelerated

Skaftafell glacier, Iceland 

 An international research team including scientists from ETH Zurich has shown that almost all the world's glaciers are becoming thinner and losing mass' and that these changes are picking up pace. The team's analysis is the most comprehensive and accurate of its kind to date.

Glaciers are a sensitive indicator of climate change -- and one that can be easily observed. Regardless of altitude or latitude, glaciers have been melting at a high rate since the mid-20th century. Until now, however, the full extent of ice loss has only been partially measured and understood. Now an international research team led by ETH Zurich and the University of Toulouse has authored a comprehensive study on global glacier retreat, which was published online in Nature on 28 April. This is the first study to include all the world's glaciers -- around 220,000 in total -- excluding the Greenland and Antarctic ice sheets. The study's spatial and temporal resolution is unprecedented -- and shows how rapidly glaciers have lost thickness and mass over the past two decades.

Rising sea levels and water scarcity What was once permanent ice has declined in volume almost everywhere around the globe. Between 2000 and 2019, the world's glaciers lost a total of 267 gigatonnes (billion tonnes) of ice per year on average -- an amount that could have submerged the entire surface area of Switzerland under six metres of water every year. The loss of glacial mass also accelerated sharply during this period. Between 2000 and 2004, glaciers lost 227 gigatonnes of ice per year, but between 2015 and 2019, the lost mass amounted to 298 gigatonnes annually. Glacial melt caused up to 21 percent of the observed rise in sea levels during this period -- some 0.74 millimetres a year. Nearly half of the rise in sea levels is attributable to the thermal expansion of water as it heats up, with meltwaters from the Greenland and Antarctic ice sheets and changes in terrestrial water storage accounting for the remaining third.

Among the fastest melting glaciers are those in Alaska, Iceland and the Alps. The situation is also having a profound effect on mountain glaciers in the Pamir mountains, the Hindu Kush and the Himalayas. "The situation in the Himalayas is particularly worrying," explains Romain Hugonnet, lead author of the study and researcher at ETH Zurich and the University of Toulouse. "During the dry season, glacial meltwater is an important source that feeds major waterways such as the Ganges, Brahmaputra and Indus rivers. Right now, this increased melting acts as a buffer for people living in the region, but if Himalayan glacier shrinkage keeps accelerating, populous countries like India and Bangladesh could face water or food shortages in a few decades." The findings of this study can improve hydrological models and be used to make more accurate predictions on a global and local scales -- for instance, to estimate how much Himalayan glacier meltwater one can anticipate over the next few decades.

To their surprise, the researchers also identified areas where melt rates slowed between 2000 and 2019, such as on Greenland's east coast and in Iceland and Scandinavia. They attribute this divergent pattern to a weather anomaly in the North Atlantic that caused higher precipitation and lower temperatures between 2010 and 2019, thereby slowing ice loss. The researchers also discovered that the phenomenon known as the Karakoram anomaly is disappearing. Prior to 2010, glaciers in the Karakoram mountain range were stable -- and in some cases, even growing. However, the researchers' analysis revealed that Karakoram glaciers are now losing mass as well.

Study based on stereo satellite images As a basis for the study, the research team used imagery captured on board NASA's Terra satellite, which has been orbiting the Earth once every 100 minutes since 1999 at an altitude of nearly 700 kilometres. Terra is home to ASTER, a multispectral imager with two cameras that record pairs of stereo images, allowing researchers to create high-resolution digital elevation models of all the world's glaciers. The team used the full archive of ASTER images to reconstruct a time series of glacial elevation, which enabled them to calculate changes in the thickness and mass of the ice over time.

Lead author Romain Hugonnet is a doctoral student at ETH Zurich and the University of Toulouse. He worked on this project for nearly three years and spent 18 months analysing the satellite data. To process the data, the researchers used a supercomputer at the University of Northern British Columbia. Their findings will be included in the next Assessment Report of the United Nations Intergovernmental Panel on Climate Change (IPCC), which is due to be published later this year. "Our findings are important on a political level. The world really needs to act now to prevent the worst-case climate change scenario," says co-author Daniel Farinotti, head of the glaciology group at ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL.

The strongest animal jaws

                  Animal Cages 

There are some animals that are characterized by decoding force, which makes them able to hunt, prey, kill, and protect themselves, and these animals are used in the jaw to perform these tasks, and vary from animal jaws and vary from animal to animal, it features strong features, teeth sharp, These animals include the following

The strongest animal jawsCrocodile: classified among the most deadly animals in the world, although the lion is the king of the jungle, but he loses in his fight with the crocodile, as he sits on the throne of the strongest jaw in the world, and is characterized by sharp teeth able to penetrate the tissues of the body and cling to, His courses are known to grind the bones of his prey, making him the deadliest among the animals of the world.

The Great White Shark: This shark spreads on almost all the shores of the world, but it is found in the beaches and beaches of Miami, South Africa and Australia. It has a high ability to sense its prey and is able to kill its prey with one

The spotted tiger, known as the jaguar or leopard, is the cat’s cat, and has the strongest bite among its cats. It is found in Australia, East Asia, sub-Saharan Africa and Africa.

A dog or an African dog is an animal that has not yet been identified as a dog or cat, but some researchers have classified it as a dog. The animal lives only in the Savannah and South Africa regions and has a strong bite that can reach its prey and break it for the first time. .

Lion: The largest animal of the cat species, is located in the Sahara South Africa, Australia, the lion is the weakest bite among the members of his faction, despite the strength of his bite, but kills his prey by strangling the trachea.

The bear is a huge animal that does not belong to either the dog or the cat. It is only classified among the wild mammals. The bear is present in many parts of the world and its characteristics vary. There are polar bears, rainforest bears and bears in southern Alaska. Very, very, very, very, very, very, very, very, very, very, very, very, very, very,.

Hippopotamus: A hippopotamus is a herbivorous animal that spends most of its time in the low-lying waters. It is found in rivers and lakes, such as the Amazon River, the Thames and the lakes in the Sahara Desert of South Africa. Although the animal is a plant, One on his territory attacks him with powerful peck, causing his death or crushing of his bones.

Where does the sponge live?

Sponge animalAlthough it may look like a plant, it is immobile and slow to respond to external stimuli. However, sponges are the simplest of the multicellular animals. The scientific term for sponges is sponges or parasites. Its body is covered with small pores. The channels that end with a large opening, or what is known as cavity, and within these channels lined rooms with specialized cells called the cells of the ring, which are sticky cells, and possesses a repressive collar and the end whip, these moving back and forth to force the water to pass through the openings, Carrying material It is similar to the shape of the amoeba, which is a primordial organism that takes food into other cells within the sponge and possesses what can be likened to the skeleton. A protein called Sponge, or a silicium oxide, which expresses the silica, or combines them, has no bones, but has grills on the outer surface as a means of self-defense, and also excreted material is not desired by fish not to eat.

Feed the spongeThe sponge feeds in the filtration method, and it does it in a very effective way. It is able to capture and eat small particles such as bacteria as well as much larger molecules, and its metabolism is very slow. However, sponges grow to large sizes so that their cavities are sufficient to accommodate a person, Tropical and tropical regions. Sponges live in the bottom of the water, spread in the seas and oceans, and there are few in fresh water such as rivers and lakes, so that they attach themselves to something solid, often a rock.

ReproductionThe sponges breed sexually and sexually, most of them are female. They have only one type, some of which play male and female roles. However, they do not fertilize themselves, but play a different role in each breeding season. , And once again, the sperm are released into the water column of the male sponges, until they find their way into the female sponges, fertilization occurs internally, then the larvae are released from the female sponges and float in the water column as plankton for only a few days and then settle down and begin In growth, multiply Also through buds where a small bud grows in the tip of the sponge and grows larger and then separates from the mother sponge and is described elsewhere.