It offers “an unbiased look at climate change.” The Landsat space program, jointly managed by NASA and the United States Geological Survey (USGS), was launched 50 years ago, in July 1972. Since then, eight satellites have been launched, three of which are still in orbit, reports Vice. This is the first civilian Earth observation space program.
“For 50 years, the mission has collected data on our planet’s forests, farms, urban areas, and fresh water, generating the longest continuous record of its kind,” NASA writes.
Through these thousands of snapshots, the Landsat program has built a mosaic of our planet seen from the sky, illustrating the changes linked to human activity over the last half century.
The shrinking Aral Sea
In the 1960s, the Aral Sea formed the fourth largest lake area in the world. In 2000, this area had already been reduced by half. This drought is due to the diversion of the two rivers by the Soviet Union to mass produce cotton.
These images captured in 2000 and then 2018 by Landsat satellites show the shrinking of the Aral Sea. “When the Aral Sea dried up, the fishermen and other communities that depended on it collapsed,” NASA writes.
“The increasingly salty water has become contaminated with fertilizers and pesticides. The dust, contaminated with agricultural chemicals, has become a public health hazard,” the agency continues.
Retreating glaciers and sprawling lakes in Tibet
Scientists often refer to the Tibetan Plateau and its many mountain ranges as the “Third Pole” because they contain the world’s largest freshwater supply outside of the polar regions. Much of this water is stored in tens of thousands of glaciers scattered throughout the region. However, rising temperatures are accelerating the melting of these ice sheets.
These images of lakes west of the Tanggula Mountains in 1987 and then in 2021 offer a view of changes caused by retreating glaciers. Therefore, the lakes have grown over time.
The melting ice in Alaska
The Columbia is a large coastal glacier in Alaska, United States, which empties directly into the sea. Since the 1980s it has begun to recede: its tip has receded 20 km and has lost more than half its thickness and volume. total.
These false-color images, taken by Landsat satellites, show how the glacier and surrounding landscape have changed since 1986, compared to 2019. Snow and ice appear in light cyan, vegetation in green, clouds in white or light orange and dark open water. blue.
“The retreat of the Columbia Glacier is contributing to global sea level rise, primarily through calving icebergs,” NASA said.
Deforestation in the Amazon
Once home to 208,000 square kilometers of forest, an area slightly smaller than the US state of Kansas, the state of Rondônia in western Brazil has become one of the most deforested areas in the Amazon. .
All major rainforests are disappearing, primarily to make way for human food production, including livestock and crops.
“While tropical deforestation meets certain human needs, it also has profound, sometimes devastating, consequences such as social conflict and human rights violations, plant and animal extinction, and climate change,” NASA details.
Urban sprawl in Shanghai
In 1960, some 110 million Chinese, or 16% of the population, lived in cities. In 2018, these figures increased to 820 million and 59%. Urbanization began in the 1980s when the Chinese government opened the country to foreign trade and investment. This series of Landsat images shows the growth of Shanghai between 1984 and 2019.
In 1984, the heart of the city was centered on the west bank of the Huangpu River, a man-made tributary of the Yangtze River. Since then, Shanghai has expanded in all directions onto what was mostly farmland.
The replacement of forests and farmland with concrete has raised the temperature of the city. Chinese researchers working with thermal sensors on Landsat have shown that in some areas of Shanghai, temperatures increased by 81% between 1984 and 2014.
Oil exploitation in Canada
Beneath Canada’s boreal forest lies one of the largest oil reserves on the planet. These Landsat satellite images show the growth of open pit mining on the Athabasca oil sands between 1984 and 2016. A trend that is expected to continue as permits are approved for mine expansion in this region.
Only 20% of oil sands are found near the surface, where they can be easily extracted. The rest of the oil sands are buried more than 75 meters underground and are extracted by injecting hot water into a well that liquefies the oil for pumping.
This exploitation has a significant impact on the environment. First, the forests must be cut down for exploitation. Additionally, it releases a number of toxins that can leach into groundwater or directly into the Athabasca River.
Also, because extracting and separating oil from sands requires energy, tar sands release more greenhouse gases than other forms of oil production.
Source: BFM TV
