• This field is for validation purposes and should be left unchanged.
home_icon-01_outline
star
  • Earth.Org Newsletters

    Get focused newsletters especially designed to be concise and easy to digest

  • This field is for validation purposes and should be left unchanged.
Earth.Org PAST · PRESENT · FUTURE
SHOP Support

In early July, Venice tested its long-delayed flood barriers, in a public demonstration of the strength of the barriers months after floods swamped the city. 

The multi-billion-euro Mose (Experimental Electromechanical Module) scheme, which was still incomplete a decade after it was due to come into service, has been plagued by corruption and ever-inflating costs. The test saw all 78 giant yellow sluice gates rising above the water for the first time, but it is not expected to be fully functional until next year. Once fully operational, the Mose flood barriers system is designed to protect Venice from tides of up to three metres, which is well beyond the current record, but some experts are concerned that it will be overwhelmed by the rising seas that recent climate change models have predicted. 

You might also like: Investments in Offshore Wind Energy Skyrocket Despite COVID-19 Shock

Additionally, the test was carried out in ideal conditions, far different from the 100kph winds and three metre waves that struck the city last November. Further, while all gates can go up, not all can currently go back down into their housings on the sea floor, due to sand in the works.

In November 2019, the worst floods in more than 50 years submerged 70% of the city at one point and rose to over 1.8 metres in some areas. Venice’s floods, called “acqua alta” (high water) are caused by rising sea levels and unusually high tides due to land subsidence that has caused the ground level of the city to sink. 

There are also concerns that Italy won’t be able to keep up with Mose’s astronomical costs, estimated at around €100m a year. Adding to the government’s borrowing to restart the economy following the COVID-19 pandemic that may push public debt to 160% of GDP, this may be an expense that is difficult to maintain.

To keep the sea level in the city from rising any more than it already is, keeping big ships out of the lagoon may help. However, Pietro Teatini, professor of hydrology at Padua university, believes that Venice should be lifted. He says that doing this by 20-30cm would help and to do this, seawater could be pumped into the already salty aquifers below the city. In 2008, it was estimated that a pilot scheme would cost €11.1m to launch and €1.4m a year to run; the full project around €80m and €10m a year. In comparison, the Mose scheme has devoured €6bn. 

Featured image by: Roberto Trombetta

Italian scientists are investigating the appearance of pink glacial ice creating the appearance of pink snow in the Alps, which is caused by algae that darkens ice and causes it to absorb heat and melt more quickly. 

No one is sure where this algae comes from, however scientists say that the pink snow observed on parts of the Presena glacier in the Alps is likely caused by the same plant found in Greenland, the blooms of which are accelerating melting rates of the ice sheet, in the “Dark Zone.”

Biago Di Mauro of Italy’s National Research Council says, “The algae is not dangerous, it is a natural phenomenon that occurs during the spring and summer periods in the middle latitudes but also at the Poles. Di Mauro previously studied the algae at the Morteratsch glacier in Switzerland, where he examined the purple ice resulting from the overgrowth of the Ancylonema nordenskioeldii algae species. 

Di Mauro noted that the combination of low snowfall volumes and high atmospheric temperatures has generated an ideal environment for algae to flourish. 

Why is pink snow bad?

Normally ice reflects more than 80% of the sun’s radiation back into the atmosphere, but as the algae appear, they darken the ice, causing it to absorb more heat and melt quicker. More algae appear as the ice melts because they are provided with vital water and air. 

Interestingly, Di Mauro notes that the presence of tourists on the mountains could also have an impact on the algae. 

You might also like: The South Pole is Warming Three Times Faster Than the Global Rate

Thermodynamics

Albedo is a non-dimensional measure that indicates how well a surface reflects solar radiation, with values ranging from 0 to 1. The higher the albedo value, the more white a surface is- conversely, the lower the albedo value, the more dark or black a surface is. On this premise, ice tends to have a much higher albedo value than the ocean, for example, which is darker in colour and absorbs more solar energy than it reflects. 

Snow has a higher albedo value than sea ice as the former requires colder temperatures in order to maintain the structural integrity of glaciers and to delay the ice from melting quickly during the warmer months. 

The algae overgrowth causing the pink hue of the Presena glacier can therefore be attributed to the decrease in albedo value, or, to the increase in solar energy absorption and, simultaneously, the decrease in light reflection. 

Similar Findings 

A study conducted in 2019 by the Cryospheric Commission of the Swiss Academy of Sciences found that the glaciers in Switzerland have shrunk 10% in the past five years- an unprecedented rate recorded from over a century of observations.

In accordance with this finding, the giant Denman Glacier in Antarctica has been shown to have retreated almost three miles in the past 22 years, and, if it thaws completely, would cause sea levels to rise by approximately 5 feet. The researchers at the University of California, Irvine, and NASA’s Jet Propulsion Laboratory raise great concern about this occurrence, and stress the importance of taking action to overcome this problem. 

This article was written in collaboration with Judy Shin.

Featured image by: Eric Chumachenco

COVID-19 has spread rapidly from China to the rest of the world. Thousands of lives have been lost and the pandemic has all but crashed the global stock market. China closed its factories, transportation systems and locked down major cities to slow the spread of the virus, and the country’s GDP is expected to drop a few percentage points this year. It may be tough to be optimistic, but an unexpected benefit of COVID-19 is the decrease in greenhouse gas emissions. 

Satellite images from NASA have shown that a drop in industrial and economic activities has resulted in reduced greenhouse gas emissions and improved air quality in Wuhan, the epicentre of the COVID-19 outbreak, over the Chinese New Year. Levels also dropped in Beijing and Hebei province, as well as Shanghai and the Yangtze River Delta region. 

The images show that pollution dropped, and didn’t rebound after the holiday. The level of PM2.5, dangerous small pollution particles, fell by 25%, while nitrogen dioxide, produced mainly by diesel vehicles, dropped by 40%. Nitrogen dioxide produces ozone, which, on the ground, is detrimental to human health, causing asthma, lung cancer and other respiratory and pulmonary illnesses. 

COVID-19 Reveals Unexpected Benefit- Reduced Emissions
Satellite images showing nitrogen dioxide emissions from January 1 2019 to February 25 2020 (Source: NASA).

PM2.5 is responsible for more than one million premature deaths in China annually and for the reduction of crop yields.

In February, during the peak of the outbreak in China, the nation’s carbon emissions dropped by about 100 million tonnes, accounting for more than 25% of carbon dioxide emissions since the outbreak began compared to the same period in 2019, roughly 6% of global carbon dioxide emissions. 

Similar drops in emissions were seen during the 2008 Olympics held in Beijing, when the government implemented measures to decrease air pollution. Measures included replacing high-emitting vehicles with increased public transportation options, shutting down some chemical plants in Beijing, raising the price of gasoline to discourage the use of cars and requiring power and chemical plants to decrease emissions by 30%. These measures caused a sudden and sharp decrease in air pollution levels in Beijing and nearby cities. The particulate matter in the air in the city decreased by an average of 18% during 2008. 

Italy

Italy has seen the greatest number of combined cases of COVID-19 of any country outside China. Public spaces have since been closed throughout the country. As people have stayed home, nitrogen emissions in Italy, particularly in the northern regions, have fallen. The European Space Agency’s Copernicus Sentinel-5P satellite tracks air pollution in the atmosphere, and the satellite has seen a sharp decrease in emissions of nitrogen dioxide over Italy since the beginning of the year. 

“Although there could be slight variations in the data due to cloud cover and changing weather, we are very confident that the reduction in emissions that we can see coincides with the lockdown in Italy causing less traffic and industrial activities,” Claus Zehner, the mission’s manager at ESA, said in a statement. 

COVID-19 Reveals Unexpected Benefit- Reduced Emissions
Images showing the decrease in nitrogen dioxide emissions over Italy from January 31 to March 8 2020 (Source: Copernicus Sentinel data processed by the ESA).

There have also been sightings of swans and fish in the port and canals of Venice due to the lack of gondolas, cruise ships and noise pollution in the city. 

The UK

While behind Italy in terms of the spread of the disease, roadside monitors in the UK are already showing significant reductions in levels of pollution. Road traffic accounts for about 80% of nitrogen oxide emissions in the UK and for the average diesel car, each km not driven prevents 52 mg of the substance entering the atmosphere. 

COVID-19 Reveals Unexpected Benefit- Reduced Emissions
Satellite data showing a reduction in the presence of nitrogen oxide over Europe (Source: Copernicus Sentinel data processed by the ESA).

Air Pollution Likely to Increase Coronavirus Death Rate

Experts have said that the health damage inflicted on people by long-standing air pollution from greenhouse gas emissions in cities is likely to increase the death rate from COVID-19 infections. 

Dirty air can cause lung and heart damage, and is responsible for at least 8 million early deaths a year. This means that respiratory infections, such as COVID-19, may have a more serious impact on those in cities and exposed to toxic fumes than others. 

Strict confinement measures in China and Italy have led to falls in air pollution. A preliminary calculation by a US expert suggests that tens of thousands of premature deaths from air pollution may have been avoided by the cleaner air in China. 

“Patients with chronic lung and heart conditions caused or worsened by long-term exposure to air pollution are less able to fight off lung infections and more likely to die. This is likely also the case for Covid-19,” said Sara De Matteis, at Cagliari University, Italy, and a member of the environmental health committee of the European Respiratory Society. “By lowering air pollution levels we can help the most vulnerable in their fight against this and any possible future pandemics.”

Scientists who analysed the SARS coronavirus outbreak in China in 2003 found that infected people who lived in areas with more air pollution were twice as likely to die as those in less polluted places. 

According to the Global Exposure Mortality Model (GEMM) developed by Bernett et al., (2018) scientists are now able to estimate the number of premature deaths from air pollution, as well as the number of premature deaths prevented because of reduced pollution levels.  

COVID-19 Reveals Unexpected Benefit- Reduced Emissions
GEMM describes the magnitude of the association between PM2.5 exposure and the probability of death in a concentration-response relationship known as the Hazard Ratio (Source: Bernett et. al, 2018).

It is estimated that the 3 weeks of reduced emissions in China during the COVID-19 outbreak may have saved 77 000 lives in the nation, mainly in the industrial region where the exposure to PM2.5 would have been highest. The actual number of lives saved may be a lot higher because people are staying at home more, which reduces their exposure to air pollutants significantly. However, it is important to note that this is difficult to quantify as it is purely statistical and associated illnesses from air pollution have long-term effects. The number of traffic accidents have also dropped. Even without the reduced emissions, the policy that made the wearing of masks in public spaces compulsory has also helped reduce exposure to pollutants; the masks also help to prevent the spread of the common cold and flu as shown by research in Hong Kong.

The experts are quick to clarify, however, that these claims are not to say that the pandemic can be seen as good for health. 

The aggressive measures taken by China and Italy to contain the COVID-19 outbreak that have resulted in reduced emissions show that it is possible to reduce emissions on a mass scale. However, the outbreak has also caused a large drop in fossil fuel demand, lowering the oil price, which may hinder the development of renewable energy. 

Unlike other satellites, PRISMA can read the chemical composition of ground and water based on light refraction. 

The first images captured by PRISMA Earth observation satellite of the Italian Space Agency (ASI) reveal the quality of water in various lakes in Italy. PRISMA mapped the lakes measuring the Nephelometric Turbidity Unit (NTU) of the waters, which assessed to be varying in different areas.

What is PRISMA?

Launched in orbit on March 22 this year with a powerful hyperspectral optical sensor, PRISMA is a first-of-its-kind earth observation tool designed to provide information about environmental monitoring, natural resource management, pollution, and crop health. 

Mapping Lake Trasimeno, the largest lake in Central Italy, PRISMA inferred that the waters are generally less turbid in the south-eastern bay, where communities of aquatic macrophytes thrive on a large scale. Macrophytes have the ability to limit resuspension of bottom sediments in a waterbody. 

Italian National Research Council (CNR-Irea) officials stated that further data processing would reveal in-depth details about the terrestrial ecosystem of Italy and other parts of Europe.

PRISMA operates in a Sun-synchronous orbit, which enables it to circle the Earth in such a way that the Sun is always in the same position as the satellite takes pictures of the planet below.

From its orbit, at about 620 kilometers of altitude, PRISMA (an Italian acronym for Hyperspectral Precursor of the Application Mission) observes the Earth on a global scale with different eyes. It includes a medium resolution camera that can view across all visual wavelengths and a hyperspectral imager that can capture a wider range of wavelengths between 400 and 2500 nanometers.

You might also like: How Airlines are Adopting Carbon Offsetting

The satellite image of Lake Trasimeno shows a turbidity gradient that varies between 3 and 6.2 NTU

“It will be able to offer an unprecedented contribution to the observation of natural resources from space and to the study of main environmental processes,” said an official release from the Italian Space Agency. “It studies the interactions between atmosphere, biosphere, and hydrosphere. It also tracks environmental and climate changes on a global level; the aftermath of anthropic activities on ecosystems.”

Why is PRISMA important?

PRISMA is able to provide valuable information to support the prevention of natural hazards like floods and man-made quandaries like soil pollution. It can also monitor fixed objects and protected areas of cultural or environmental significance, aids actions to humanitarian crises, and explores mineral resources. 

“Unlike the passive satellite sensors currently operating, which record the solar radiation reflected by our planet in a limited number of spectral bands, PRISMA will be able to acquire 240 spectral bands,” said the ISA statement. “This will help us to refine our knowledge concerning natural resources and climate change.”

PRISMA was developed by a consortium led by OHB Italy and Leonardo. 

Subscribe to our newsletter

Hand-picked stories once a fortnight. We promise, no spam!

SUBSCRIBE
Instagram @earthorg Follow Us