A grim picture of drought-yellow France seen from space

Explore interviews with researchers, photographers, travelers who have witnessed the changing world under the yoke of global warming.

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[EN VIDÉO] Heat Waves or Heat Waves: What’s the Difference?
In summer, we hear about heat peaks, heat waves and heat waves. The difference is not clear, but it is useful for weather warning or health warning planning.

This is a satellite image Sentinel d Interesting that it provides a lot of information.” Some of which are not visiblethe eyes naked “, explains Clement Albergel, researcher of the office the climate AESA (European Space Agency). You should know that Sentinel 3 has a “ Radiometers that measure surface temperatures “It’s not about” temperatureair In the meteorological sense of the term but the actual amount of radiant energy from the Earth – and which indicates the actual temperature of the Earth’s surface ” Of course the higher air temperatures are reflected in the Earth’s surface temperature values.

Sentinel 3 measured “ Record temperatures, 48 ​​degrees Celsius in the UK, 60 degrees Celsius in Spain “This Sentinel measures 3,” Combined with other satellite instruments on boardEarth observation Also measure surface temperature “, useful for development” Long time series Observing Earth from space, and better understand how they evolve. This allows something type of validation Climate models and some climate assumptions

The European Space Agency recently installed one Information center Surface temperature covers the period 1996-2020 which is ” shows a steady increase in land surface temperature on a global scale of 0.2°C per decade with very strong regional variability ” This picture of France, showing a country covered with vegetation in a state the drought Advanced, good explanation Duration of heat waves and their succession heat wave which affects France and Europe

These are the wave of the heat which is consistent with unusually high temperatures observed for several consecutive days,” Most worrying about the vulnerability of our society is climate extremes “This is the heat wave we’ve been experiencing in Western Europe since June.” Its clear signs global warming Caused by human activity, as shown Various reports of the Intergovernmental Panel on Climate Change (IPCC)

they are “us” Provide insight into our future climate “, warns Clement Albergel

they are “us” Provide insight into our future climate “, warns Clement Albergel. The researcher would like to point out that the latest report published by the IPCC “ Indeed indicates that heat waves and, in general, extreme weather-climate events are increasing in intensity and severity. frequency Because climate change is linked to human activities and especially emissions of Green house gas in the air

Conditions conducive to fire

As we see in the news (in Spain, Portugal, France, Greece, UK…), these extreme heat conditions and high temperatures are accompanied by favorable conditions for fires, ” That is, the humidity in the air is low, low amount of rainfall And dry vegetation creates a high risk of fire as soon as there is an ignition source “These things have been seen Conditions conducive to fires are often observed for longer and longer periods

Added to this is another consequence of this continuation of heat waves, ” Associated with the low rate of rainfall, is the phenomenon of drought “Many rivers in Europe have now dropped to record levels, which has happened Severe reaction onagricultureA sector that consumes a lot of water for irrigation

like everyone Natural disaster and according to their characteristics (resolution, swath, revisit, spectral band, etc.), Earth observation satellites are called upon to aid rapid damage assessment and rescue. To aid their organization, the population is called upon to provide logistical support and predict the evolution of natural disasters. In the case of fires, satellites make it possible to follow their evolution from space, and above all the different characteristics of fires such as ” Dry and fire-prone areas, active and smoldering fires, burnt areas and smoke and gas emissions

There is assessment of burnt area with satellite images Also of interest is another to serve as a baseline for monitoring forest regeneration “If we put aside the concept of risk monitoring, it is very” Grading of burned areas over long periods of time is important in the context of climate change studies “Because when plants burn, it” These emit significant amounts of greenhouse gases and particulate matterthe atmosphere. It is estimated that about 25% to 35% of greenhouse gases result from combustion biomass ” This is a variable that is being developed as part of the ESA Climate Change Initiative with Biomass Mission. The satellite, scheduled for launch in 2023, will be dedicated to forest monitoring and observation, One of the most important natural resources on Earth, to better understand the cycle Carbon

To better understand the role of Earth observation satellites used to detect fires from space, it should be noted that this detection is based on two principles. the physical. The first is related to I’mexception Thermals that occur when vegetation burns, including ground surface temperatures that are significantly higher than their surroundings, can be reported as active fires. This signal is quite easy to detect, but usually lasts very little (a few hours, during the fire). ” A second possibility is to monitor changes in surface reflectance ( reflected light by our planet). Because of this change Burnt plants are dark in color, this the stain Left in the fire “This signal is less clear from space but more” Permanent, especially in something Biomewhere its effect the fire Fires persist for months or even years, although in tropical regions they may disappear within weeks.

Better predict drought and promote sustainable agriculture

To take into account climate change and its consequences, Copernicus, the European Commission’s global Earth observation programme, will be equipped with new families of satellites” Structure of the Copernicus program expansion mission As Clement Albergel affirms, “ noWe are working on the new high priority satellite mission of the Copernicus program “Each of them will help to address the scientific, political and social aspects of climate change as well as the major environmental challenges expected, viz Sustainable agricultural management, food security, polar ice monitoring, and all will be used to understand climate change

Related to the topics of this article (Heat wavesdrought and fire), among these future missions, we can mention as an example the Land Surface Temperature Monitoring Mission (LSTM) which ” sensor Infrared High spatio-temporal resolution thermal (Sentinel 3 enhancement) to provide global scale measurements of surface, day and night temperatures across the Earth “, as well as an instrument which ” will observe stress To support crop irrigation and practices at field levelirrigation More durable

Satellite data analysis for mapping, monitoring and forecasting of Earth’s natural resources Makes it possible to understand what changes are happening, as well as when and where “This mission will make it possible to respond more specifically to the needs of European farmers who need to make agriculture more sustainable. A context of water resource depletion and environmental change ” In view of the growing scarcity the waterhis ” Use for agriculture should be more efficient

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