GREEN HOUSE

 GREENHOUSE EFFECT

Greenhouse effect, a warming of Earth’s surface and troposphere (the lowest layer of the atmosphere) caused by the presence of water vapour, carbon dioxide, methane, and certain other gases in the air. Of those gases, known as greenhouse gases, water vapour has the largest effect. The atmosphere allows most of the visible light from the Sun to pass through and reach Earth’s surface. As Earth’s surface is heated by sunlight, it radiates part of this energy back toward space as infrared radiation. This radiation, unlike visible light, tends to be absorbed by the greenhouse gases in the atmosphere, raising its temperature. The heated atmosphere in turn radiates infrared radiation back toward Earth’s surface. (Despite its name, the greenhouse effect is different from the warming in a greenhouse, where panes of glass transmit visible sunlight but hold heat inside the building by trapping warmed air.) Without the heating caused by the greenhouse effect, Earth’s average surface temperature would be only about −18 °C (0 °F). On Venus the very high concentration of carbon dioxide in the atmosphere causes an extreme greenhouse effect resulting in surface temperatures as high as 450 °C (840 °F).

Sunlight makes the earth habitable. While 30 percent of the solar energy that reaches our world is reflected back to space, approximately 70 percent passes through the atmosphere to the earth’s surface, where it is absorbed by the land, oceans, and atmosphere, and heats the planet. This heat is then radiated back up in the form of invisible infrared light. While some of this infrared light continues on into space, the vast majority indeed, some 90 percent gets absorbed by atmospheric gases, known as greenhouse gases, and redirected back toward the earth, causing further warming.

For most of the past 800,000 years much longer than human civilization has existed the concentration of greenhouse gases in our atmosphere was between about 200 and 280 parts per million. (In other words, there were 200 to 280 molecules of the gases per million molecules of air.) But in the past century, that concentration has jumped to more than 400 parts per million, driven up by human activities such as burning fossil fuels and deforestation. The higher concentrations of greenhouse gases and carbon dioxide in particular is causing extra heat to be trapped and global temperatures to rise.

Earth’s greenhouse gases trap heat in the atmosphere and warm the planet. The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapor (which all occur naturally), and fluorinated gases (which are synthetic). Greenhouse gases have different chemical properties and are removed from the atmosphere, over time, by different processes. Carbon dioxide, for example, is absorbed by so-called carbon sinks such as plants, soil, and the ocean. Fluorinated gases are destroyed only by sunlight in the far upper atmosphere.

How much any one greenhouse gas influences global warming depends on three key factors. The first is how much of it exists in the atmosphere. Concentrations are measured in parts per million (ppm), parts per billion (ppb), or parts per trillion (ppt); 1 ppm for a given gas means, for example, that there is one molecule of that gas in every 1 million molecules of air. The second is its lifetime how long it remains in the atmosphere. The third is how effective it is at trapping heat. This is referred to as its global warming potential, or GWP, and is a measure of the total energy that a gas absorbs over a given period of time (usually 100 years) relative to the emissions of 1 ton of carbon dioxide.

Radiative forcing (RF) is another way to measure greenhouse gases (and other climate drivers, such as the sun’s brightness and large volcanic eruptions). Also known as climate forcing, RF quantifies the difference between how much of the sun’s energy gets absorbed by the earth and how much is released into space as a result of any one climate driver. A climate driver with a positive RF value indicates that it has a warming effect on the planet; a negative value represents cooling.

Since the start of the Industrial Revolution and the advent of coal-powered steam engines, human activities have vastly increased the volume of greenhouse gases emitted into the atmosphere. It is estimated that between 1750 and 2011, atmospheric concentrations of carbon dioxide increased by 40 percent, methane by 150 percent, and nitrous oxide by 20 percent. In the late 1920s, we started adding man-made fluorinated gases like chlorofluorocarbons, or CFCs, to the mix.

In recent decades we’ve only picked up the pace. Of all the man-made emissions of carbon dioxide the most abundant greenhouse gas released by human activities, and one of the longest-lasting from 1750 to 2010, approximately half were generated in the last 40 years alone, in large part due to fossil fuel combustion and industrial processes. And while global greenhouse gas emissions have occasionally plateaued or dropped from year to year (most recently between 2014 and 2016), they’re accelerating once again. In 2017, carbon emissions rose by 1.6 percent; in 2018 they increased by an estimated 2.7 percent.

HUMAN NEGATIVE EFFECTS ON THE ENVIRONMENT

Deforestation

Sadly, the world’s forests are being cut down at a rapid rate. An area of the Amazon rainforest roughly the same size as Jamaica was deforested between August 2020 and July 2021, the highest rate of deforestation since 2012. Since trees absorb carbon dioxide from the atmosphere, they’re an essential resource for mitigating global heating. But when they’re cleared and burned the opposite occurs – carbon is released back into the atmosphere.

Overfishing

The use of industrial-scale fishing techniques to meet our demand for fish is depleting our oceans. For example, bottom trawl fishing is a method used in many parts of the world, whereby a large weighted net is swept along the ocean floor to catch fish. But this can harm corals and pick up unwanted species, including dolphins and sea turtles, in a process known as bycatch.

Burning Fossil fuels

It’s a well-documented fact that the burning of fossil fuels is the prime culprit for climate change. When oil, gas and coal are burned, they release carbon dioxide and other harmful greenhouse gases, which trap heat in the Earth’s atmosphere and cause it to warm up. As well as being used for our energy supply, these fuels play a big role in producing plastic, steel, concrete and other important materials. Fossil fuels are currently used to supply 80% of the world’s energy.

Plastic Pollution

Plastic is a double-edged sword. On one hand it’s an incredibly useful, versatile and cheap material, but on the other, it’s an environmental disaster. Virgin plastic is made from natural gas or oil, meaning it directly supports the fossil fuel industries, but this wonder-material also lasts hundreds of years without breaking down. This has led to swathes of plastic waste to accumulate in the ocean.

Water Pollution

Unfortunately, plastics aren’t the only harmful substances polluting our oceans and waterways. Sewage is one of the biggest causes of water pollution: around 80% of the world’s wastewater is released into the ecosystem without adequate treatment, contaminating our oceans, lakes and rivers. Contaminants from sewage deplete oxygen levels in water, which are essential to the survival of fish and other aquatic wildlife. What’s more, the pollution of already-limited freshwater supply could be detrimental to human health.

Light Pollution

Around 83% of the world’s population lives under light-polluted skies. While there’s no doubt that artificial light has revolutionised our lives in the past century, coupled with the vast numbers of people moving to cities, the sheer quantity of artificial lights is effectively stealing the night sky. Not only does this hinder our ability to see the stars, it’s having grave consequences on plants and animals. For example, light pollution has been found to disrupt migratory birds’ flight patterns, impact animals’ sleep and wake cycles, and disturb the hatching habits of sea turtles.

Air Pollution

When harmful gases including carbon dioxide, nitrogen oxide, sulfur dioxide and volatile organic compounds (VOCs) are released into the air, they have grave consequences on both the environment and human health. Currently, 90% of the world’s population breathes air that contains more pollutants than recommended as safe by the World Health Organization (WHO). Air pollution has myriad knock-on effects on the environment too: it contaminates soil and waterways, can lead to acid rain (due to sulfur dissolving in the air), and can lead to birth defects and diseases in animals.

Pesticides

Farmers around the world are increasingly using pesticides to protect their crops from being destroyed by pests. Unfortunately, however, pesticides are causing insects to die off en masse – according to a 2019 report, insects could disappear within a century if pesticide usage continues. Insects are essential for the proper functioning of our ecosystems, as they provide food for other species, pollinate plants and recycle nutrients back into the environment.

Fertilizer

Another aspect of modern farming that’s wreaking havoc on our ecosystems is the use of fertilisers. While organic materials including manure and plants have been used for centuries, the invention of artificial fertilisers in the 1920s led to vast quantities of nitrogen to leak into soil and waterways. In the last 100 years, the amount of man-made nitrogen present in the environment has doubled. Excessive quantities of nitrogen not only accelerate climate change, but poison plants and animals.

Overpopulation

It’s an unavoidable fact that each person on Earth increases carbon emissions. So the world’s burgeoning population, which is currently increasing by 80 million people per year, is a climate concern. But it’s important to note that people living in wealthy countries have had a far bigger impact on carbon emissions and most victims from climate change are from less-developed nations. In fact in 2018, two of the world’s biggest economies, the US and China, were responsible for almost half of all carbon emissions.

Oil Extraction

Oil is a nonrenewable energy source with finite reserves, meaning we can’t keep using it forever. What’s more, burning oil releases carbon dioxide into the atmosphere, worsening global warming. A study published in the journal Nature in 2020 revealed that we may be underestimating methane emissions from fossil fuels by up to 40%. Methane, which is responsible for around 40% of global warming, is one of the biggest byproducts released when oil is burned for energy consumption.

Oil Spill

It’s not just the burning of oil that poses a climate concern. Oil spills, which occur when oil from a rig spills out into the surrounding environment, have long lasting ecological consequences. In April 2010, an explosion at the BP owned Deep water Horizon rig in the Gulf of Mexico led to the biggest oil spill in history. At its worst point, it was thought up to 60,00 barrels of oil were leaking out into the surrounding waters per day. Despite cleanup efforts, the spill had horrific impacts on wildlife: many animals were wiped out while others continue to suffer long-standing health effects.