Climate Changes: Emission of Greenhouse Gases, Human & Nature Contribution

Climate is a statistical description of weather conditions and their variations, including both averages and extremes, and climate change refers to a change in these conditions that persists for an extended period of time. Greenhouse gases like carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons are thought to be the main contributors to climate change through the Greenhouse Effect. These gases are very efficient in trapping heat into the atmosphere; therefore, resulting in the global rise of temperature which has led to significant global changes. There are contributors to global change and they have been divided into natural and human or anthropogenic causes as the major contributor.

According to Holli Riebeek, the author of “Global Warming,” nature contributes to climate change by emitting CO2. Natural disasters like volcanos contribute to climate change by emitting CO2. However, the amount of CO2 they emit is relatively small as compared to the amount of CO2 that is being released by human activities. According to NASA, on average, volcanoes emit between 130 and 230 million tons of CO2 per year. However, by burning fossil fuels, people release in excess of 100 times more, about 26 billion tons of CO2, into the atmosphere every year.

The emission of greenhouse gases has increased dramatically from the industrial revolution. Scientists believe human activities are changing the natural greenhouse. Over the last century, the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide. This happens because the burning process combines coal with oxygen in the air to make CO2. There are other factors that contribute as well like the clearing of land for agriculture, a shift in vegetation patterns, industrial emissions, urbanization, and other human activities have increased the concentration of greenhouse gases but to a lesser extent. According to the Australian Greenhouse Office, the world depends on fossil fuels such as oil, coal, and natural gas for 80% of its energy needs. Therefore, that makes it very hard to switch from fossil fuels to any other forms of energy because we depend on fossil fuels to a large degree.

Changes in the climate system due to climate forcings are not to be confused with natural climate fluctuations. Indeed, even within a relatively stable period, the systems that make up and influence the global climate still naturally fluctuate. These fluctuations or oscillations can have a large effect on the climate, both locally and on a global scale. For example El Niño, La Niña, and the El Niño Southern Oscillation (ENSO). ENSO is a climate pattern that occurs, roughly every 5 years, across the tropical Pacific Ocean. El Niño describes extensive warming of the ocean surface across the eastern and central equatorial Pacific lasting three or more seasons. When this oceanic region switches to below normal temperatures, it is called La Niña

Conclusively this, therefore, shows that naturally the climate has been changing but that has not caused significant global changes, it is human activities that have led to drastic global changes. Industrial activities that our modern civilization depends on have raised atmospheric carbon dioxide levels and other human activities like deforestation and urbanization have contributed as well. Studies have shown that if nothing is done about this, there will be more changes and global temperatures will increase more.

According to NASA reports the Earth's average temperature has increased about 1 degree Fahrenheit during the 20th century and scientists had predicted these effects in the past and that they would result from global climate change which is now occurring. Sea levels are rising and oceans are becoming warmer. Loss of sea ice, and ice on rivers and lakes is breaking up earlier and glaciers have shrunk. Longer more intense heat waves and droughts, plant and animal ranges have shifted and trees are flowering sooner. Longer, more intense droughts threaten crops, wildlife, and freshwater supplies. From polar bears in the Arctic to marine turtles off the coast of Africa, our planet’s diversity of life is at risk from the changing climate.

Observed Increase in temperatures

The temperature increase of 1 degree Celsius looks like a minor adjustment but great evidence from the changes in annual precipitation, rise in sea level, extreme weather events, and melting of glaciers and ice sheets which has led to predictions that Antarctica might disappear from the earth surface, shows that it has had a great impact on climate.

This figure illustrates how the average land and ocean surface temperature has changed between 1880 and 2020. The annual temperature average has always varied, with cold and warm periods alternating. It is however evident that each of the last four decades has been successively warmer at the Earth’s surface than any preceding decade since 1880. The temperature increase is widespread across the world, but there are important regional variations and warming has been most marked in the northern Polar Regions. 

Observed ocean acidification

Ocean acidification refers to decreasing levels of pH in the ocean, which makes the sea more acidic. About 30% of anthropogenic CO2 emissions have been absorbed by the oceans. This leads to ocean acidification. According to the IPCC, the pH of ocean surface water has decreased by 0.1 since the beginning of the industrial era.

Change In annual Precipitation overland

Scientific observations have shown that changes are occurring in the amount, intensity, frequency, and type of precipitation. These generally exhibit large natural variability, and El Niño and other natural climate fluctuations have a substantial influence. Over the past century, however, pronounced long-term trends in precipitation amounts have been observed: significantly wetter in eastern North and South America, northern Europe, and northern and central Asia, but drier in the Sahel, southern Africa, and the Mediterranean, and southern Asia. Moreover, widespread increases in heavy precipitation events have been observed, even in places where total amounts have decreased.

Observed ocean warming

More than 60% of the net energy increase in the climate system is stored in the upper ocean and ocean warming dominates the increase in energy stored in the climate system. Oceans account for more than 90% of the energy accumulated between 1971 and 2010. 60% of the net energy increase is stored in the upper ocean (0-700 m) and about 30% is stored in the ocean below 700 m. The ocean warming is largest near the surface, being the upper 75 m warmed by 0.11°C per decade over the period 1971 to 2010.

Observed sea level rise

There has been a rise in the sea levels and over the past century, the global mean sea level rose by 0.19m. The loss of Greenland and Antarctica ice sheets, glacier mass loss, and ocean thermal expansion from warming together explain about 75% of the observed global mean sea-level rise since the early 1970s. Thermal expansion has led to the rise in sea level because when water heats up it expands whereas glaciers and ice sheets have melted quickly due to the rise in temperatures.

Observed decrease in arctic sea ice extent

Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice has continued to decrease in extent. The natural process of ice melting during summer and having precipitation as snow in winter has been disrupted by the increase in temperatures that has led to more ice melting. Observations have been made in Nepal, studies show that temperatures in Nepal are increasing at a rather high rate. Shrestha et al. 

Observed Changes in Physical and Biological Systems

Biological changes include, for example, species loss and ecosystem alterations. Physical changes include, for example, changes in snow cover, changes in glacier density/coverage, and run-off. The percentages associated with the observations indicate how many of the reported changes are due to a warming environment. 

Climate as the greatest threat to the ecosystem has made the Great Barrier Reef and coral reefs worldwide which plant and animal ranges to shift. The Great Barrier Reef off the coast of Australia has seen two massive bleaching events over the span of two years. And that's led to a widespread die-off of the corals. Through close observations of the world's largest coral reef system, scientists are taking stock of the extent of the damage from higher water temperatures due to global warming. They mapped the patterns of heat exposure on more than 1,400 miles of reef and monitored which corals are dying, in order to understand the future of these reefs. This has really been an event that is changing the character of these reefs, and now that marine heatwaves are coming more frequently and more severely, it is expected that this sort of damage to keep occurring on coral reefs around the world.

Observed extreme weather events

Whenever an episode of extreme weather – heat wave, floods, drought, etc. hits the headlines, many people tend to blame human-induced climate change. Determining whether a specific, single extreme event is due to a specific cause, such as increasing greenhouse gases, is difficult, if not impossible, for two reasons being that, extreme weather events are caused by a combination of factors, and a wide range of extreme events is a normal occurrence even in an unchanging climate.

At the same time, observations have shown a large increase in the number of strong hurricanes globally since 1970. Specifically, the number of strong hurricanes increased by about 75% since 1970. The IPCC points out that a trend towards longer storm duration and greater storm intensity is closely correlated with tropical sea surface temperature. This might be an indication of a causal link between global warming and hurricane destructiveness. However, the high variability in tropical storms and hurricanes over several decades and a lack of systematic high-quality observation before satellite observations make it difficult to detect long-term trends.

Increased temperatures warm the oceans and warmer oceans mean hurricanes and tornados become more intense. When hurricanes start, they usually pick up energy from the oceans and as a result of warmer water in the oceans because of the greenhouse effect, hurricanes have more energy. Therefore, hurricanes become more intense. Now if the water was colder that gives less energy to hurricanes and makes it less intense. For example, hurricane Katarina which was a level 5 hurricane that made landfall on Florida and Louisiana in August 2005, caused massive damage and deaths.

Conclusively climate has changed in the past years going back to the effects of the industrial revolution due to the massive emission of gases into the atmosphere. There are three main factors that have contributed to this, being; human contribution, nature contribution, and emission of greenhouse gases. This has affected plants and animals, changes in precipitation, rise in sea level Without urgent action to cut greenhouse gas emissions, the world will continue to feel the effects of a warming Arctic, rising sea levels, changes in climate and precipitation patterns, increasing severe weather events, and loss of fish stocks, birds and marine mammals and this might mean the disappearance of some islands in the future as well and melt of glaciers and ice sheets.