Mapping Pollution from Space
Over the last few decades there have been many projects that have been monitoring pollution and gathering environmental information from satellite technology. One example is the NASA Aura spacecraft that is monitoring air quality on a global scale.
In 2004 the space craft was launched and since then has provided a valuable temporal record of the global air quality. It is recording trace gas signatures in the atmosphere from their unique spectral signatures. There are several instruments on board. One of these, the Ozone Monitoring Instrument, has observed and measured changes in nitrogen dioxide (NO2) levels over time. Nitrogen dioxide is a noxious gas emitted by motor vehicles, power plants and other industrial facilities. The instrument also measures pollutants such as ozone (O3), sulphur dioxide (SO2), and atmospheric aerosols. These particular atmospheric constituents pose a serious threat to human health and agricultural productivity. The pollutants can be measured at “near urban levels” which provides a high-level of information accuracy.
The results of recording atmospheric data for almost a decade, over the period 2005-2014, show that nitrogen dioxide has increased in several places and declined in others. The information captured for this chemical compound shows great global, regional and city level variation in pollution levels.
Aura has recorded a decline in nitrogen dioxide levels over most European cities for example. This is likely to be due to much stricter vehicle emission standards. Cities showing the largest decreases include Madrid (48 percent), Lisbon (47 percent), and Barcelona (44 percent).
In Asia generally there has been an increase in pollution in a number of large cities such as Dhaka, the Bangladesh capital, where nitrogen dioxide increased by 79 percent. This is the highest increase recorded. Other cities such as Lahore in Pakistan and India have also experienced growth in pollution levels. Interestingly China, where in Beijing there have been many reports of very bad air quality, has shown mixed results. Some cities have shown steep rises in pollution whilst others have experienced a decline. Shanghai saw levels drop by 30 percent, Hong Kong dropped by 28 percent, and Beijing showed a 10 percent decline. This can be attributed to policy decisions to improve the air quality in these urban centres. Other cities in the north and central plains of China saw the pollution levels rising.
Having long term monitoring such as this can be invaluable to showing the impact of policy decisions on improving environmental conditions. Here it is the atmospheric air quality. For some images of the changes described here have a look at the NASA Earth Observatory web site article.
Carbon Dioxide Levels Rapidly Increase In 2015
At a more down to earth base of the United States National Oceanic and Atmospheric Administration’s (NOAA) Mauna Loa Observatory in Hawaii, monitoring of carbon dioxide concentration continues. The NOAA observatory has monitored global carbon dioxide levels for the past 56 years. It has shown that levels rapidly increased during 2015. During the year levels of atmospheric carbon dioxide increased by 3.05 parts per million. This may not seem much but it is highly significant as carbon dioxide levels have not accelerated as much for hundreds of thousands of years. Worryingly it is also the fourth consecutive year where carbon dioxide (CO2) had increased by more than 2 parts per million (ppm).
The current El Nino event, or warm climate phase, which occurs regularly over 2 to 7 years disrupting global weather patterns. This event also has partially accounted for an increase in the CO2 levels (this has been observed in previous El Nino events). Changes to weather has an impact on terrestrial systems such as forests and other plant life which respond to changes in weather, precipitation and drought. As a result there is a corresponding natural increase in carbon dioxide concentration levels.
This big increase in CO2 is not, however, generally a natural phenomenon; NOAA state “high emissions from fossil fuel consumption are driving the … growth rate over the past several years.” This big increase is partially explained by El Nino but is mostly attributed to human emissions or anthropogenic climate disruption (ACD). See the NOAA news item detailing the measurements here.
Global monitoring is showing global impacts of man on the environment. Both NOAA and NASA’s Aura are two examples of scientific monitoring that is alerting us to change whether it has been encouraging news or more concerning. We ignore the science at our peril.