What is global warming and climate change and what can we do about it?
The Royal Society provides the following succinct explanation of how heat-trapping greenhouse gases lead to global warming:
The Sun serves as the primary energy source for Earth’s climate. Some of the incoming sunlight is reflected directly back into space, especially by bright surfaces such as ice and clouds, and the rest is absorbed by the surface and the atmosphere. Much of this absorbed solar energy is re-emitted as heat (longwave or infrared radiation). The atmosphere in turn absorbs and re-radiates heat, some of which escapes to space. Any disturbance to this balance of incoming and outgoing energy will affect the climate.
If all heat energy emitted from the surface passed through the atmosphere directly into space, Earth’s average surface temperature would be tens of degrees colder than today. Greenhouse gases in the atmosphere, including water vapour, carbon dioxide, methane, and nitrous oxide, act to make the surface much warmer than this because they absorb and emit heat energy in all directions (including downwards), keeping Earth’s surface and lower atmosphere warm [Figure B1]. Without this greenhouse effect, life as we know it could not have evolved on our planet. Adding more greenhouse gases to the atmosphere makes it even more effective at preventing heat from escaping into space. When the energy leaving is less than the energy entering, Earth warms until a new balance is established.
Greenhouse gases emitted by human activities alter Earth’s energy balance and thus its climate. Humans also affect climate by changing the nature of the land surfaces (for example by clearing forests for farming) and through the emission of pollutants that affect the amount and type of particles in the atmosphere.
Scientists have determined that, when all human and natural factors are considered, Earth’s climate balance has been altered towards warming, with the biggest contributor being increases in CO2 from human activity – primarily the burning of fossil fuels.
The science of global warming is complex, but the increasing sophistication of computer models has helped achieve a high degree of accuracy in determining the consequences locally, nationally, and internationally.
As a result of global warming, the residents of Gloucester can expect to experience hotter and drier springs and summers, warmer and wetter autumns and winters. The secondary effects of these climate changes are an increased number of heatwaves, wildfire, and drought incidents impacting public health and supplies of food and water; and an increase in average rainfall and a large increase in high rainfall events, leading to property damaging and service disrupting floods.
Reducing emissions and undertaking climate adaptation work today can, however, mitigate many of the worst effects of global warming tomorrow. That is why the City Council is undertaking both strategic and practical work in in this area.
Further reading:
The Basics of Climate Change by the 361-year-old Royal Society, one of the most respected scientific institutions in the world, provides a useful introduction to the subject, with accompanying graphics:
National Geographic’s Climate Change 101 with Bill Nye provides an accessible audio/visual introduction to climate science, which can be found here:
https://www.youtube.com/watch?v=EtW2rrLHs08
You can find out more about global warming-induced impacts of climate change on Gloucester via the Met Office Local Authority Climate Service:
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