Ozone layer is present in

The amount of ozone in the stratosphere varies naturally throughout the year as a result of chemical processes that create and destroy ozone molecules and as a result of winds and other transport processes that move ozone molecules around the planet. Over the course of several decades, however, human activities substantially altered the ozone layer.

The loss of the ozone layer, which risked exposing people to harmful ultraviolet rays from the sun, is on track to be completely recovered by 2040 across the world, aside from the polar regions, Following alarm over the loss of ozone in the 1980s, the ozone layer has been steadily improving in the wake of the 1989 Montreal protocol, an international agreement that has helped eliminate 99% of ozone-depleting chemicals, such as chlorofluorocarbons (CFCs) that were used as solvents and refrigerants. The UN said the action taken on the ozone layer had also bolstered the more ponderous response to the climate crisis – CFCs are also greenhouse gases and their continued uncontrolled use would have raised global temperatures by as much as 1C by the middle of the century, worsening an already dire situation where planet-heating gases are still not declining. “Ozone action sets a precedent for climate action,” said Petteri Taalas, secretary-general of the World Meteorological Organization, which unveiled the progress report, which is conducted every four years, on Monday. “Our success in phasing out ozone-eating chemicals shows us what can and must be done as a matter of urgency to transition away from fossil fuels, reduce greenhouse gases and so limit temperature increase.” The unified global response to dealing with CFCs means that the Montreal agreement should be considered “the most successful environmental treaty in history and offers encouragement that countries of the world c...

The evolution of Earth’s climate contains many components. And new research has shown just how critical the ozone layer is to the surface temperature of the Earth. Without an ozone layer, our planet would be 3.5 Kelvin cooler. Many feedback and forcing mechanisms play a role in But this is a highly simplistic picture. In reality our temperature and climate depend on everything from the Remove All Ads on Universe Today Join our Patreon for as little as $3! Get the ad-free experience for life While the ozone layer of the Earth’s supper atmosphere is critical for blocking ultraviolet radiation from the Sun, most climate models have ignored the role of ozone in studying the Earth’s climate. However, researchers have studied the impact of the ozone layer in a new paper We have not always had an ozone layer. Before the emergence of life, ozone was essentially non-existent in our atmosphere. And the Earth spent billions of years with only a minimal ozone layer. It is only in relatively recent times that it has stabilized to the thick levels that we see in the present day. And while the molecular oxygen that makes up a good fraction of the Earth’s atmosphere plays little role in climate, the ozone layer does. To study the impact of the ozone layer, the researchers employed a suite of simulations of the Earth’s climate. They varied the amount of ozone in the upper atmosphere and allowed the Earth’s temperature to reach an equilibrium. They found that the presence of ozone has a war...

We live at the bottom of an invisible ocean called the atmosphere, a layer of gases surrounding our planet. Nitrogen and oxygen account for 99 percent of the gases in dry air, with argon, carbon dioxide, helium, neon, and other gases making up minute port ions. Water vapor and dust are also part of Earth’s atmosphere. Other planets and moons have very different atmospheres, and some have no atmospheres at all. The atmosphere is so spread out that we barely not ice it, yet its weight is equal to a layer of water more than 10 meters (34 feet) deep covering the entire planet. The bottom 30 kilometers (19 miles) of the atmosphere contains about 98 percent of its mass. The atmosphere— air—is much thinner at high altitudes. There is no atmosphere in space. Scientists say many of the gases in our atmosphere were ejected into the air by early volcanoes. At that time, there would have been little or no free oxygen surrounding Earth. Free oxygen consists of oxygen molecules not attached to another element, like carbon (to form carbon dioxide) or hydrogen (to form water). Free oxygen may have been added to the atmosphere by primitive organisms, probably bacteria, during photosynthesis. Photosynthesis is the process a plant or other autotroph uses to make food and oxygen from carbon dioxide and water. Later, more complex forms of plant life added more oxygen to the atmosphere. The oxygen in today’s atmosphere probably took millions of years to accumulate. The atmosphere acts as a giga...

The world’s oceans are a vast repository for gases including ozone-depleting chlorofluorocarbons, or CFCs. They absorb these gases from the atmosphere and draw them down to the deep, where they can remain sequestered for centuries and more. Marine CFCs have long been used as tracers to study ocean currents, but their impact on atmospheric concentrations was assumed to be negligible. Now, MIT researchers have found the oceanic fluxes of at least one type of CFC, known as CFC-11, do in fact affect atmospheric concentrations. In a study appearing today in the Proceedings of the National Academy of Sciences, the team reports that the global ocean will reverse its longtime role as a sink for the potent ozone-depleting chemical. The researchers project that by the year 2075, the oceans will emit more CFC-11 back into the atmosphere than they absorb, emitting detectable amounts of the chemical by 2130. Further, with increasing climate change, this shift will occur 10 years earlier. The emissions of CFC-11 from the ocean will effectively extend the chemical’s average residence time, causing it to linger five years longer in the atmosphere than it otherwise would. This may impact future estimations of CFC-11 emissions. The new results may help scientists and policymakers better pinpoint future sources of the chemical, which is now banned worldwide under the Montreal Protocol. “By the time you get to the first half of the 22nd century, you’ll have enough of a flux coming out of the ...

The ozone layer is one layer of the stratosphere, the second layer of Earth’s atmosphere. The stratosphere is the mass of protective gases clinging to our planet. The stratosphere gets its name because it is stratified, or layered: as elevation increases, the stratosphere gets warmer. The stratosphere increases in warmth with elevation because ozone gases in the upper layers absorb intense ultraviolet radiation from the sun. Ozone is only a trace gas in the atmosphere—only about three molecules for every 10 million molecules of air. But it does a very important job. Like a sponge, the ozone layer absorbs bits of radiation hitting Earth from the sun. Even though we need some of the sun's radiation to live, too much of it can damage living things. The ozone layer acts as a shield for life on Earth. Ozone is good at trapping a type of radiation called ultraviolet radiation, or UV light, which can penetrate organisms’ protective layers, like skin. This then may damage DNA molecules in plants and animals. There are two major types of UV light: UVB and UVA. UVB is the cause of skin conditions like sunburns, and cancers like basal cell carcinoma and squamous cell carcinoma. People used to think that UVA light, the radiation used in tanning beds, is harmless because it doesn’t cause burns. However, scientists now know that UVA light is even more harmful than UVB, penetrating more deeply and causing a deadly skin cancer, melanoma, and premature aging. The ozone layer, Earth’s sunsc...