Anthropogenic Greenhouse Gas Emissions., - Coggle Diagram
Anthropogenic Greenhouse Gas Emissions.
chiefly of environmental pollution and pollutants) originating in human activity
Anthropogenic action has caused “the Enhanced Greenhouse Effect”
Incoming short wave radiation outgoing long wave radiation absorbs greenhouse gases
The enhanced greenhouse effect
Since the early nineteenth century the volume of GHGs in the Earth’s atmosphere has increased rapidly
The most striking change has been an increase in CO2 by one-third, from 280 ppm in 1800 to just over 400 ppm today.
This has created an enhanced greenhouse effect due almost entirely to the consumption of fossil fuels, deforestation and other land-use change.
As the Earth’s climate has warmed, change has been amplified by increases in evaporation and therefore atmospheric water vapour, and the melting of permafrost in the Arctic releasing CH4 and CO2.
The enhanced greenhouse effect increases absorption of long-wave radiation in the atmosphere and raises global temperatures.
Anthropogenic greenhouse gas emissions
Greenhouse gases warm the Earth and its atmosphere by absorbing outgoing, long wave radiation
The main GHGs are water vapour, carbon dioxide (CO2) and methane (CH4). For the past 200 years, some of these gases have been increasing in the atmosphere. This trend, directly or indirectly, is the result of human activities.
CO2 is a significant GHG and accounts for more than three-quarters of all anthropogenic GHG emissions. Before 1800 its concentration in the atmosphere was fairly stable at around 280 ppm.
The increase in atmospheric CO2 is accelerating and nearly half of the increase has occurred since 1960. Today atmospheric CO2 is 414 ppm.
Atmospheric concentrations of CH4 are much smaller and are measured in parts per billion. Direct measurements of CH4 began only in 1984. In that year, at sea level, they were 1735 ppb; by 2009 this figure had increased to 1890 ppb.
Although a much slower rate of increase than CO2, CH4 is a more potent GHG, with 25 times the global warming potential. Today CH4 represents around 15 per cent of all GHG emissions
Carbon Dioxide: Burning fossil fuels (coal, oil, and gas), slash and burn agriculture, decomposition of organic matter, transportation, electricity production, residential uses, cement production, landfill sites.
Methane: Anaerobic respiration of methanogenic bacteria in wetlands, animals, oil and gas production.
Nitrous Oxide: Land use change, deforestation, fertilizer emissions agriculture land, aviation.
Reasons for rising GHG emissions
The huge surge in demand for energy due to industrialisation and technological advances, particularly in manufacturing and transport.
Massive global population growth, from 1 billion in 1800 to 7.4 billion in 2015, together with rising living standards.
Land-use change, especially deforestation and the draining of wetlands for food production and urban development.
Despite the development of nuclear power and renewables, our dependence on fossil fuels
remains. Today fossil fuels still supply 87 per cent of the world’s energy.
2/3 of global anthropogenic GHG emissions comes from burning of fossil fuels, which release 10 billion tonnes of CO2 annually
Although coal is no longer the leading fossil fuel, coal production in the early twenty-first century reached record levels. Two of the world’s largest economies, China and India, are powered largely by coal. Unfortunately, coal is also the dirtiest fossil fuel: it emits nearly twice as much CO2 as natural gas and 20 per cent more than oil.
The changing balance of anthropogenic emissions around the world
Most CO2 and other GHG emissions in the period 1850 to 1960 originated from the industrialised economies of North America and Europe.
Asia’s emissions have increased massively while those of North America and Europe have stabilised and in the case of Germany and the UK have actually declined.
Historically the USA has dominated CO2 emissions. Its historic emissions since 1850 (22 per cent) are almost equal to the combined emissions of China, Russia, Germany and the UK.
Since 1960, however, significant regional shifts have occurred in emissions of CO2 and other GHGs.
Early in the twenty-first century, China, with its reliance on coal and its insatiable demand for energy to sustain its explosive economic growth, overtook the USA as the world’s leading emitter of CO2.
Global emissions remain highly uneven: the top ten CO2-emitting countries account for nearly 80 per cent of all emissions.
ACs such as the USA, Australia, Germany and the UK are well ahead of the emerging economies of China and India. For example, the USA and Australia both emit an average of 17 tonnes/year per person of CO2, compared with 5.4 tonnes by China and just 1.4 tonnes by India.
When emissions of other GHGs such as CH4 from land-use changes are added to CO2 from fossil fuel combustion, a slightly different regional picture emerges. Although China and the USA remain in first and second place, Brazil and Indonesia currently rank as the third and fourth largest emitters of GHGs. This is due to the effects of large-scale deforestation in Amazonia and Indo-Malaysia.