Climate change

What is climate change?

Climate refers to the general composition of a variety of atmospheric conditions over the long term, such as a span of 20 to 30 years. In contrast, "weather" refers to the actual climate conditions in any given short term period.

Climate change is a change in the weather found in places around the world. This could be a change in how much rain a place usually gets in a year. Or it could be a change in place's usual temperature for a month or season.

Climate change is also a change in Earth's climate. This could be a change in Earth's usual temperature. Or it could be a change in where rain and snow usually fall on Earth.

Is the Earth's climate changing?

It's no surprise now that the atmosphere is warming at a fast pace. This effects the entire world. This is due to the increase in the amount of carbon dioxide in the air, which has risen by about 25% in the last 150 years.

Global warming is primarily caused by the excessive discharge of greenhouse gases in industrialized countries, mostly from burning fossil fuels.

Climate change is measured with global variations that happen over long scales of time and diverse climatic events. Climate changes are brought about by natural causes and human activity over the last century.

The United Nations uses the term climate change to refer exclusively to changes in global climate brought about by human activity as we alter the atmospheric composition through burning fossil fuels and deforestation of large stretches of land.

What gases make up the atmosphere?

The dry composition of the atmosphere is mostly 98% nitrogen and oxygen. There also exist small amounts of water vapor, argon, ozone, carbon dioxide and other particulates.

Water vapor is most important from the meteorological point of view because it produces condensation and precipitation, forming clouds, rain, dew, snow, etc.. Water vapor also absorbs solar and terrestrial energy and serves as the principal source for developing storms and stabilizing the Earth's atmosphere.

The Earth receives electromagnetic radiation from the Sun, ultraviolet, invisible and infrared short waves. In turn, it emits long infrared waves. These two flows of energy should be in balance. Greenhouse gases allow the short wave radiation to penetrate, BUT, they also absorb the long wave radiation that should be leaving our atmosphere. The greenhouse gases act like a heat blanket around a rock (like our Earth) held to the flame (like the sun). Once the rock is removed from the flame (night time), the blanket (greenhouse gases) does not allow the rock to cool down as quickly because the heat is trapped inside. This effect is called the "greenhouse effect" or global warming.

What is Carbon Dioxide?

Carbon dioxide is a greenhouse gas that absorbs and radiates heat. Warmed by sunlight, Earth’s land and ocean surfaces continuously radiate thermal infrared energy (heat). Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb that heat and release it gradually over time, like bricks in a fireplace after the fire goes out. Without this natural greenhouse gas Earth’s average annual temperature would be below freezing instead of close to 60°F. But increases in greenhouse gases have tipped the Earth's energy budget out of balance, trapping additional heat and raising Earth's average temperature. 

Carbon dioxide is the most important of Earth’s long lived greenhouse gas. It absorbs less heat per molecule than the greenhouse gases methane or nitrous oxide, but it’s more abundant and it stays in the atmosphere much longer. Increases in atmospheric carbon dioxide are responsible for about two-thirds of the total energy imbalance that is causing Earth's temperature to rise.

Ice caps melting and sea levels rising.

Melting polar ice caps as well as melting glaciers in the Himalayas and Greenland is a clear fact.

Coastal communities face immediate consequences of global warming, as experienced by many victims of recent natural disasters. With rising warm tropical waters, it is no longer discussed if sea levels are rising. It is now how fast it's rising. 

In addition to rising sea levels, coastal communities are also subject to swells in the ocean waves, which can also be devastating. Already, waves have increased by average of 3 meters on the Pacific and 2 meters on the Caribbean.

The effects of Global warming

The destabilization of climate from increased greenhouse gasses and rise of temperatures and water vapor in excess quantities creates more frequent and more severe storms with flooding and alternating periods of sustained droughts. The weather becomes highly unpredictable and the delicate balance of Nature is challenged to adapt or die.

According to the World Health Organization, just a small rise in temperatures can cause a drastic rise in the number of extreme temperature related deaths. Diseases threaten the global community like Covid 19, as do droughts and starvation caused by scarcity of water and food.

The Ozone Hole

The hole in the ozone layer over Antarctica is also related to global warming or the greenhouse effect. Chloroflurocarbons or CFC's are greenhouse gases that contribute to global warming and destroy the ozone. Normal atmospheric circulation is affected by high temperatures and chemical reactions that produce ozone are deleteriously affected making the hole grow ever larger. Local data measuring the total ozone present in the air in Central America shows the ozone levels falling below normal ranges.

To reverse the trends in global warming, it will be necessary for the nations of the world to dramatically reduce their dependence on fossil fuels, reduce the current rate of deforestation, and find methods to capture and store the excess atmospheric carbon.

Sequestering carbon by planting trees is an effective way of combating carbon build-up. It has been estimated that 100 to 200 million hectares of new forest would be needed to sequester 1,000 million tons of carbon annually (Woodwell, 1992). Five million hectares are currently being planted every year. Therefore, an intensified effort over the next thirty years to double the number of plantations would provide a carbon sink capable of sequestering one-eighth of the present global level of carbon emissions.

Do Oceans absorb Carbon?

The ocean covers about 70% of Earth's surface are one of the best absorbers of carbon dioxide, sequestering along with trees over 60% of what is currently generated. So, it's not surprising that it plays a large part in Earth's environment. The ocean also absorbs carbon dioxide from Earth's atmosphere. The additional heat and carbon dioxide in the ocean can change the environment for the many plants and animals that live here.

The ocean is structured into two layers: the superficial layer has contact with the atmosphere and can extend up to 50 meters in the tropics and up to various kilometers in the poles, and the underlying layer which is deeper, colder and more saline, and responsible for moving 90% of the oceanic volume. A change in temperature in the oceans can cause a change in global climate by 30 times.

Winds induce the superficial ocean currents to transport heat from the tropical zones to the poles. This is called the Thermohaline circulation or the global conveyor belt that is the ocean.

But the conveyor is delicately balanced and vulnerable and has shut down or changed direction many times throughout Earth's history. Each time the Conveyor belt has shifted gears it has caused significant global temperature changes within decades. Wallace S. Broeker of the Columbia University Record Reports.

Thermohaline currents and climate change.

The hot superficial currents propel the band including the Gulf current that arrives at the North Atlantic current. In winter, the hot water transfers its heat to the large masses of frigid cold air above Canada, Greenland, and Iceland, which are covered in ice. The masses of air towards the east make the climate in Northern Europe similar to that in North America. Without this functioning system, the temperatures in the Northern Atlantic region would fall by 20 degrees in just ten years.

We are all in the same boat together. 

 

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