As solar radiation hits Earth’s atmosphere, some of it is absorbed by gases called greenhouse gases that keep heat from radiating back out into space.
Scientists refer to this phenomenon as the greenhouse effect and it directly contributes to global warming.
Greenhouse gases trap heat
Earth’s atmosphere consists of gases such as carbon dioxide, water vapor, methane and nitrous oxide that contribute to its greenhouse effect by blocking solar radiation from quickly dissipating into space. By absorbing solar radiation as energy that heats air and surface temperatures instead of dissipating away to space, our planet achieves a higher equilibrium temperature than would otherwise exist.
The greenhouse effect functions similarly to a glass building that lets sunlight into and keeps plants warm even on cold winter days, and this process plays out in our atmosphere, on an enormous scale and for much longer. Understanding this phenomenon is crucial as human impact on climate change increases dramatically over time.
Solar radiation that reaches Earth’s atmosphere primarily consists of visible light (ranging in wavelength from violet to red), passing freely through air but absorbing heat at its point of contact with Earth. Some of this heat then radiates upwards and outwards into space while some is reflected back down onto its surface, becoming part of greenhouse gases’ trapping mechanisms.
Greenhouse gases such as carbon dioxide and water vapor absorb infrared radiation while still allowing visible light through. This happens because their molecules are loosely bound together, which allows vibrations of infrared radiation absorption to cause these greenhouse gases to act like blankets to keep some heat nearer the planet’s surface.
Methane, another greenhouse gas, is produced by living organisms such as cows and decomposed organic material, while being released into the environment via human activities like burning fossil fuels or draining swamps and landfills or by volcanic activity.
Carbon dioxide and other greenhouse gases occur naturally in the atmosphere, but their concentration has steadily been growing since the Industrial Revolution of the late 1700s due to human activities such as burning fossil fuels, clearing forests and farming. The increase in atmospheric concentrations of these gases has resulted in global warming: overall warming of our atmosphere that cannot be stopped.
Humans are releasing more greenhouse gases
Human activity, in particular the burning of fossil fuels, has contributed to an alarming increase in greenhouse gases such as water vapor, carbon dioxide, methane and nitrous oxide in our atmosphere. These greenhouse gases amplify natural greenhouse effects that lead to global warming.
Some greenhouse gases occur naturally, such as water vapor, carbon dioxide and methane that is released into the air by evaporating water or breathing organisms such as plants and animals; volcanoes also emit greenhouse gases into both atmosphere and oceans; however others are created through human activities.
Coal mining, oil drilling and the burning of fossil fuels are major sources of carbon dioxide and nitrous oxide emissions; forest destruction contributes significantly too. Furthermore, agricultural technology and livestock farming produce greenhouse gases as well.
Humans release greenhouse gases into the atmosphere when they release greenhouse gases into it, disrupting Earth’s climate system and altering animal habitats, altering water and wind patterns and changing snowfall and rainfall patterns, leading to changes in snowfall/rainfall patterns or leading to extreme weather events such as heatwaves/floods/droughts etc.
Carbon dioxide concentration in the atmosphere has seen an approximately 30-percent rise since the start of industrial revolution in 1700. Methane, nitrous oxide and hydrochlorofluorocarbons also continue to increase at an alarming rate.
People account for roughly 23% of global man-made greenhouse gas emissions into the atmosphere today. This includes electricity and heating consumption, transportation emissions, food processing operations, construction activities, agriculture/forestry practices and various other forms of human activities that produce these emissions.
Carbon dioxide emissions are one of the primary contributors to atmospheric warming. They arise from fossil fuel combustion and breakdown, as well as biological decay processes such as decomposition. Carbon emissions are offset by physical, chemical, and biological mechanisms known as “sinks,” which work to remove it from our atmosphere.
These sinks include living vegetation such as forests, which absorbs the most carbon dioxide emissions. Unfortunately, much of what humans release into the atmosphere comes from deforestation and other forms of land use change; and methane, nitrous oxide and fluorinated gases released as by-products of various industrial, agricultural and household activities as well.
The climate is changing
Human activity has altered Earth’s climate more quickly than at any other point in history, accelerating climate change faster than ever before. We’re witnessing rising temperatures, rising sea levels, more intense wildfires and changes to precipitation patterns such as drought and flooding – changes which impact people worldwide; though those most impacted tend to reside in developing nations which typically lack sufficient resources to cope.
Scientists largely attribute recent global warming to greenhouse gases – specifically carbon dioxide and methane – that trap heat in the atmosphere, such as burning fossil fuels (coal, oil, natural gas) as well as human activities such as deforestation, agriculture and land clearing. Human activities account for most greenhouse gas emission; other climatic influences like volcanoes or natural fluctuations cannot fully explain observed temperature shifts globally.
Over Earth’s long history, solar radiation and thermal emissions have generally been in equilibrium. But since the industrial revolution began, greenhouse gas concentration has fluctuated drastically in our atmosphere; when this occurs, the balance between incoming solar radiation and outgoing thermal radiation shifts, and thus global temperatures warm or cool accordingly to restore this equilibrium.
Greenhouse gas concentrations in the atmosphere have reached record highs over millions of years. By itself, doubling carbon dioxide would cause global average temperatures to increase by approximately one degree Celsius; however, our complex climate system can have other consequences (known as feedbacks ) that compound this warming impact and further amplify it.
Temperature increases, sea level rise and other climate change effects are expected to become even more pronounced as emissions of greenhouse gases increase. Some changes, like loss of ice sheets and melting permafrost could become irreversible over hundreds or even thousands of years, while others such as rising sea levels and more frequent storms are already happening faster than many species can adapt.
What can we do?
A healthy climate system relies on an equilibrium between certain gases, with greenhouse gas emissions disrupting that equilibrium by trapping more heat in the atmosphere and heating it further, altering snowfall patterns, sea level rise and other environmental consequences. An excessive increase in greenhouse gases trapping heat heats Earth even further by trapping more heat than usual and warming its surface temperature further still. This results in greater temperature changes across its surface as a whole and causes negative environmental consequences, including changes to snowfall and rainfall patterns, sea-level rise and other environmental problems affecting its environmental impacts.
Human activity generates large quantities of greenhouse gas emissions, but there are ways to lower them. Lowering emissions helps prevent or mitigate climate change by lowering temperatures and restoring equilibrium within ecosystems.
One way we can reduce emissions is to use energy efficiently. We can do this by installing energy efficient lighting, Energy Star appliances such as water heaters and HVAC systems, using renewable sources of power for buildings, or carpooling or taking public transportation instead of driving ourselves or taking rides on bikes.
Another way of reducing emissions is through choosing materials that do not release greenhouse gases during production of goods. Plastics alone generate 1.8 billion metric tonnes annually of these harmful emissions; there are alternatives that don’t. To further decrease our carbon footprint, it would also help if we bought less stuff and/or purchased secondhand when possible; alternatively if purchasing new items, select those made of recyclable materials or that run off renewable energy sources like solar.
Protecting forests and oceans should also be our focus, with initiatives ranging from reducing deforestation, pollution, biodiversity preservation, forest and marine conservation efforts, fishing reduction activities as well as shipping activities that create pollution being among those we can consider effective methods of doing so.
Reduce greenhouse gas (GHG) emissions is of paramount importance, and we must do this through energy; agriculture, food and land use; forests and land use; transport; as well as by improving natural and built environments such as water resources and infrastructure resiliency.
GHG emission reduction is an international effort that will take years to accomplish, yet we have an outstanding opportunity this century to make considerable strides by using renewable energy sources and improving efficiency across every sector.
