Greenhouse Gases: Future of Climate Change

Climate Change

Our planet is warming. The Earth’s normal temperature has risen by 1.5°F over the last century and is likely to increase by another 0.5 to 8.6°F over the next century. Small changes in the planet’s average temperature can cause significant and potentially dangerous shifts in climate and weather.

The evidence is undeniable. Rising global temperatures have accompanied weather and climate change. As a result, rainfall patterns in many places have changed, causing more floods, droughts, heavy rain, and frequent and severe heat waves.

The planet’s oceans and glaciers have also undergone significant changes, with oceans warming and becoming more acidic, ice caps melting, and sea levels rising. These and other changes will almost certainly challenge our society and environment as they become more pronounced in the coming decades.

Climate change is any significant change in climate measurements that lasts for an extended period. Climate change, in other words, includes substantial changes in temperature, precipitation, or wind patterns, including other effects, that take place over several decades or longer.

Future of Climate Change

Effects of Increasing Greenhouse Gas Concentration:

Greenhouse gas concentrations in the atmosphere will continue to rise unless our annual emissions of billions of tonnes are significantly reduced. Enhanced concentrations are expected to do the following:

• Increase the average global temperature.
• Influence precipitation patterns and amounts. Reduce ice and snow cover, as well as permafrost.
• Increase the acidity of the oceans by raising sea levels.
• Increase the number, severity, and duration of extreme events.
• Changes in ecosystem characteristics pose more significant threats to human health.

These variations will have an impact on our food supply, water resources, infrastructure, ecosystems, and also on our own health.

Future Changes Will Be Based on Many Aspects

The magnitude of future climate variations will be determined by what we do now to reduce greenhouse gas emissions.

• The more we emit greenhouse gases, the greater the magnitude of future changes.
• Natural climate influences (for example, volcanic activity and changes in sun intensity) and natural processes within the climate system (e.g., changes in ocean circulation patterns)

Computer models of the climate system are used by scientists to better understand these issues and project future climate changes.

Impact of Greenhouse Gas

Many greenhouse gases are long-lasting in the atmosphere. As a result, even if emissions ceased to rise, atmospheric greenhouse gas concentrations would rise and remain elevated for hundreds of years.

Furthermore, even if we stabilized concentrations and kept the composition of today’s atmosphere constant (which would necessitate a significant reduction in current greenhouse gas emissions), surface air temperatures would continue to rise.

This is because it takes several years for the oceans, which store heat, to fully respond to higher greenhouse gas concentrations. The ocean’s response to rising greenhouse gas concentrations and temperatures will continue to have an impact on climate for the next several decades to hundreds of years. 

Greenhouse Gases

The greenhouse effect causes heat to be maintained in the atmosphere.

When sunlight strikes the Earth’s surface, it can be reflected back into space or absorbed by the planet. After absorbing some of the energy, the planet emits some of it back into the atmosphere as heat (also known as infrared radiation).

Greenhouse gases like water vapour (H₂O), carbon dioxide (CO₂), and methane (CH₄) absorb energy, slowing or stopping heat loss to space. GHGs act as a blanket, keeping the Earth warmer than it would be otherwise. This is commonly described as the “greenhouse effect.”

The primary greenhouse gases (GHGs): Carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and several other GHGs are among the most significant GHGs directly emitted by humans.

1. Carbon dioxide:

Carbon dioxide is the main greenhouse gas responsible for recent climate change. CO₂ is naturally absorbed and emitted as part of the carbon cycle, via plant and animal respiration, volcanic eruptions, and ocean-atmosphere exchange.

Human activities, such as the use of fossil fuels and changes in land use, emit large amounts of CO₂, causing atmospheric concentrations to rise. In the distant past, some volcanic eruptions released large amounts of CO₂.

However, according to the United States Geological Survey (USGS), human activities now emit more than 135 times as much CO₂ as volcanoes each year. Every year, humans emit more than 30 billion tons of CO₂ into the atmosphere.

The resultant buildup of CO₂ in the atmosphere is analogous to a bathtub filling up with water, with more water flowing from the faucet than the drain can handle.

2. Methane:

 It is a hydrocarbon gas produced through both the sources such as natural sources and human activities, like the decomposition of waste materials in landfills, agriculture, and particularly in rice cultivation, as well as ruminant digestion process and manure management related to domestic livestock.

Methane is a very active greenhouse gas than carbon dioxide, but it is also one of the component that is much less abundant in the atmosphere.

3. Nitrous oxide:

It is very powerful greenhouse gas emitted by various modes like methods of soil cultivation, particularly the use of commercial and organic fertilizers, burning of fossil fuels,  production of nitric acid, and burning of biomass.

Other Greenhouse Gases:

1. Water vapor:

It is  very abundant greenhouse gas, but mainly, it acts as a feedback to the climate. When Earth’s atmosphere gets warm, water vapor increases. By this, the possibility of clouds and rain increases. This makes the feedback mechanism to the greenhouse effect.

2. Chlorofluorocarbons (CFCs):

Synthetic compounds are used in a number of products, but now mainly regulated in production and release to the atmosphere by international agreement for their capacity to add to the damage of the ozone layer. CFC’s are too greenhouse gases.

Because projecting far-off future emissions and other human factors that influence climate is difficult, scientists employ a variety of scenarios based on various assumptions about future economic, social, technological, and environmental conditions.

RCP – Date taken from Representative Conceptration Pathway

Future Temperature Shifts

Global warming has already been observed over the last several decades. Temperatures are expected to rise further in the future. The following key temperature-related changes are predicted by climate models.

The most important global projections

• By 2100, average global temperatures are expected to rise by 0.5°F to 8.6°F, with a likely increase of at least 2.7°F for all scenarios except the most aggressive mitigation of greenhouse gas emissions.
• Except in the most aggressive mitigation scenario studied, global average temperature is expected to rise by at least twice as much in the next 100 years as it did in the previous 100.
• Ground-level air temperatures are likely to continue to rise faster over land than over the oceans.

Precipitation and Storm Events in the Future

Precipitation patterns and storm events, including both rain and snowfall, are also likely to change. Some of these changes, however, are less certain than those associated with temperature. Future precipitation and storm changes are expected to vary by season and region, according to projections.

Some regions may experience less precipitation, others may experience more precipitation, and still others may experience little or no change.

In most regions, the amount of rain falling during heavy precipitation events is expected to increase, while storm tracks are expected to shift poleward. The following precipitation and storm changes are predicted by climate models.

The Most Important Global Projections

Global average annual precipitation is expected to rise through the end of the century, though changes in precipitation amount and intensity will vary significantly by region.

The average intensity of precipitation events will most likely increase. This will be especially noticeable in tropical and high-latitude regions, which are also expected to see an increase in precipitation overall.

The wind strength associated with tropical storms is expected to increase. The amount of precipitation falling as a result of tropical storms is also expected to rise.

Annual average precipitation is likely to rise in some areas while falling in others. The figure to the right depicts projected regional precipitation differences under two emission scenarios.

Ice, Snowpack, and Permafrost in the Future

The extent of Arctic sea ice is already diminishing. Since around 1970, the area of snow cover in the Northern Hemisphere has decreased. Temperatures of permafrost in Alaska and much of the Arctic have risen over the last century.

It is likely that sea ice will continue to decline, glaciers will shrink, snow cover will decrease, and permafrost will thaw over the next century. The following sections describe potential changes to ice, snow, and permafrost.

Permafrost is described as any ground that has been completely frozen 32°F (0°C) or colder—for at least two years. These permanently frozen grounds are most common in mountainous areas and at higher latitudes—near the North and South Poles.

The Most Important Global Projections

Models predict a 15% decrease in the extent of annually averaged Arctic sea ice and a 25% decrease in the area covered by Arctic sea ice at the end of summer for every 2°F of warming (September). It should be noted that this decrease has no effect on sea level rise.

The coastal parts of the Greenland and Antarctic ice sheets are likely to melt or slide into the ocean in the coming years. If the rate of melting of this ice accelerates in the twenty-first century, the ice sheets could significantly contribute to global sea level rise.

Glaciers are expected to continue shrinking in size. The rate of melting is likely to increase further, contributing to sea-level rise.

Future Sea-Level Rise

Warming temperatures cause sea level rise by expanding ocean water, melting mountain glaciers and ice caps, and causing portions of the Greenland and Antarctic ice sheets to melt or flow into the ocean.

Global sea level has increased by about 7.5 inches since 1870.

 Future sea level rise estimates vary by region, but global sea level is likely to rise faster in the next century than it has in the previous 50 years.

 Global sea level is expected to rise another 1 to 4 feet by 2100, with an uncertainty range of 0.66 to 6.6 feet.

Thermal expansion, ice caps, and small glaciers all contribute to sea level rise, but the effects of climate change on ice sheets in Greenland and Antarctica are less well understood and remain an active area of research.

Changes in ice sheets are expected to account for 1.2 to 8 inches of sea-level rise by the end of the century.

Future relative sea level rise will be influenced by regional and local factors for specific coastlines around the world. For example, relative sea level rise is affected by changes in land elevation caused by subsidence (sinking) or uplift (rising). Assuming that these historical geological forces persist, a 2-feet rise in global sea level by 2100 would result in the relative sea level rise shown below:

In New York City, the height is 2.3 feet.

In Hampton Roads, Virginia, the elevation is 2.9 feet.

Galveston, Texas, has a high tide of 3.5 feet.

1 foot at Washington’s Neah Bay Local changes in currents, winds, salinity, and water temperatures, as well as proximity to thinning ice sheets, all influence relative sea level rise.

Ocean Acidification in the Future

Many marine species suffer from ocean acidification, including plankton, mollusks, shellfish, and corals. The availability of calcium carbonate will decrease as ocean acidification worsens. Calcium carbonate is an important component of the shells and skeletons of many marine organisms.

Coral calcification rates are expected to fall by more than 30% if atmospheric CO₂ concentrations double. If CO₂ levels rise at their current rate, the combination of climate change and ocean acidification could slow coral growth by nearly half by 2050.