Effect of Climate Change

What is Climate Change?

Let's begin by looking at the definition of climate change.

Something that needs to be stressed is that a specific weather event that takes place in a particular area, say a very hot day in December in Massachusetts, is not indicative of climate change; a hot day in December is a weather-related event rather than a climate-related one.

What is the Difference Between Climate and Weather?

Climate is the long-term weather patterns in a specific area. For example, the climate of a desert biome is characterized by very little rainfall throughout the year and a very drastic change in temperature from day to night daily. Climate does not describe the rainfall or temperature in one specific day.

On the other hand, weather refers to the short-term atmospheric conditions of a specific area. When we look at weather forecasts, it usually describes the atmospheric conditions within 48 hours. While there are long-term forecasts available (for example, those that exceed a week) they can be unreliable.

What are the Causes and Effects of Climate Change?

Climate change has been around even before the emergence of humans. However, human activity has increased the rate of climate change and, in turn, humans have also been suffering the impact of climate change. In this section, we will discuss the various causes and effects of climate change throughout Earth's history.

What are the Causes of Cimate Change?

There are many causes of climate change, including human activity. Let’s briefly discuss some of these causes.

Pre-Industrial Era

Prior to the 1780s, there were three main natural causes of climate change: the Milankovitch cycles, variations in solar intensity, and volcanic eruptions.

1. The Milankovitch cycles

Each cycle lasts anywhere between 19,000 to 100,000 years. This means that we can expect climate change due to changes in the Earth’s orbit every 19,000 years at the minimum.

2. Variations in solar intensity

Solar intensity refers to the amount of energy or power that the sun emits within a given period. An increase in solar intensity corresponds to an increase in the Earth’s temperature. Likewise, a decrease in solar intensity corresponds to a decrease in the Earth’s temperature. Variation in solar intensity is one of the possible explanations for the Little Ice Age, a period during the 1550-1850 AD when the Earth was unusually cool.

3. Volcanic eruptions

Volcanic eruptions–while these may last only a few days–release solids and gasses that can cause changes in the climate over several years, which are considered short-term climate changes. These solids and gasses include carbon dioxide, carbon monoxide, hydrogen, water vapor, sulfur dioxide, and hydrogen sulfide.

Volcanic eruptions usually cause a decrease in temperature. For example, when Icelandic volcanoes erupted in 1783, large amounts of sulfuric oxide were released into the atmosphere, causing haze-effect cooling. Haze effect cooling is when ash, dust, or other suspended particles block out sunlight and result in a decrease in global temperatures. Such an event caused the lowest average recorded winter temperatures in 1783-1784.

Industrial Revolution (the 1750s) to present

The Industrial Revolution was characterized by drastic changes in human society: technological innovations were sped up, leading to advances in agriculture and improvements in production. Fossil fuels, especially coal, were used to power these new technologies. Because burning fossil fuels releases carbon dioxide, the Industrial Revolution led to a steady increase in the concentration of carbon dioxide in the atmosphere.

Figure 1. This illustration shows the steel and iron industries that were present in Trenton, New Jersey during the 1840s. Source: Internet Archive Book Images, via Wikimedia Commons.

Let's discuss the two main causes of climate change since the Industrial Revolution: greenhouse gasses and human activities, both of which are interrelated.

1. Greenhouse gases

Greenhouse gases are the atmospheric gasses that trap heat energy from the sun as it strikes the Earth, similar to the glass roof of a greenhouse that prevents heat from escaping. The greenhouse gasses that contribute to global climate change include carbon dioxide, ozone, methane, nitrous oxide, and water vapor.

Greenhouse gases cause the warming of the Earth, a phenomenon called the greenhouse effect. This process is described as follows:

1. Nearly half of the sun’s energy passes through the greenhouse gasses as it strikes the Earth.

   • Some of the sun’s energy is re-radiated back into space.

   • Some of the sun’s energy is converted into thermal energy, causing the Earth’s surface to warm up.

2. Heat energy radiates from the Earth towards space.

3. Greenhouse gases reflect back some of this energy towards the Earth, trapping heat in the atmosphere.

It is important to note that while almost all greenhouse gases are emitted only through human activities (for example, hydrofluorocarbons and perfluorocarbons), some occur naturally but are found at higher levels because of human activities (for example, methane and carbon dioxide).

2. Human activities

As mentioned earlier, the burning of fossil fuels including gasoline, natural gas, and coal releases carbon dioxide into the atmosphere.

Much of our day-to-day activities that require energy rely on fossil fuels: from heating our homes and running our vehicles to operating large industries and manufacturing sites. In fact, 81% of the total energy of the United States is derived from coal, oil, and natural gas, which are all fossil fuels. Other human activities that release carbon dioxide include livestock production, deforestation, and industrial processes like cement manufacturing.

Another greenhouse gas, methane is released when organic matter is broken down by bacteria without free oxygen. As such, methane emissions can be attributed to livestock production, the decay of organic waste in landfills, and the burning of natural gas (which is primarily composed of methane).

What are the Effects of Climate Change on the Environment?

The Permian extinction event, the decrease in ice and increase in sea levels in modern times, changes in periodic events, and range shift are just some of the effects of climate change on the environment. Let's go through each one.

The Permian Extinction Event

Climate change is one of the primary causes of the Permian extinction event which took place over 251 million years ago when the Earth was in one of the warmest periods in its entire geologic history. By the end of this period, around 70 percent of all terrestrial species and 84 percent of all marine species became extinct.

Decrease in Ice and Increase in SeaLevels

In modern times, climate change has led to several global events such as the glacier recession (the shrinking or retreat of glaciers) of the Glacier National Park in Montana. From 150 glaciers in 1850, the park has only around 24 glaciers that are bigger than 25 acres in 2010. Similarly, ice sheets in Greenland and the Antarctic are also shrinking at an alarming rate.

The loss of ice in these areas is contributing to the rise of global sea levels, with an average of 1.8mm increase per year. Figure 3 below shows the changes in sea levels between 1993 to 2018.

Figure 3. This map shows the changes in sea level from 1993 to 2018. Source: NOAA, Public domain, via Wikimedia Commons.

The rise in sea levels will cause shorelines to be engulfed, which will in turn cause islands to shrink and affect the distribution of species that inhabit these areas. Some islands may even disappear entirely.

Change in Periodic Lifecycle Events

Many organisms are also affected by climate change, especially changes in temperature and precipitation. For example, 385 plant species in Great Britain are found to be flowering 4 and a half days earlier than was observed in the past 40 years.

This change alone could damage the ecosystem because flowering plants interact with or even depend on other organisms such as their pollinators. A change in the flowering period of flowering plants could lower their chances of survival and reproduction if it occurs when their pollinators are not present.

Range Shift

Climate change alters precipitation patterns, making habitats potentially unsuitable for the species that inhabit them. Because of the rise in global temperatures, colder climates will be shifted closer to the poles, forcing species to change the geographic areas that they occupy, a phenomenon called range shift.

Range shift has been observed in some European bird species whose ranges have moved 91 km to the north. Range shift has also been observed in various species of butterflies, freshwater fishes, and mammals. Range shift can be dangerous to species as it may cause mismatches in food availability and breeding times.

What are the Effects of Climate Change on Humans?

Climate change has serious effects on humans too. Climate change can increase the frequency of extreme weather events such as wildfires, storms, flooding, and drought. These extreme weather events can affect human health by causing shortages in food supplies, contaminating bodies of water (whether for consumption, livelihood, or recreational use), and damaging vital infrastructures.

Health Effects of Climate Change

Climate change can also increase the geographic range of vector-borne diseases. For example, ticks that carry Lyme disease move within a specific geographic range that is limited by temperature. With the increase in temperature, ticks have become active at an earlier time and have expanded their range northward. Similarly, the migration pattern of birds that are host to mosquitos that carry the West Nile virus is influenced by changes in winter temperature and precipitation; in turn, this can change the reproduction rate of the mosquitos.

Can we Lessen or Reverse the Harmful Effects of Climate Change?

While we cannot reverse the harmful effects of climate change overnight, we can lessen the rate of climate change by reducing the emission of greenhouse gasses.

Hypothetically, if humans were to stop emitting greenhouse gasses today, global temperatures would still rise for another couple of decades because ocean currents would bring to the surface the excess heat that was stored in the depths of the ocean.

However, after this excess heat is released into space, global temperatures would soon stabilize, and–even without human intervention–natural processes would begin to remove extra carbon dioxide from the atmosphere, leading to a gradual decline in global temperatures.

Can Human Activities have Positive Effects on Climate Change?

As the emission of greenhouse gasses contributes the most to global climate change, activities that can have a positive impact on climate change must center on reducing such emissions. One vital action that humans can take is to transition to sustainable energy sources such as solar and wind energy.

Individuals, too, can contribute to the reduction of climate change by making conscious decisions in our day-to-day lives, including saving energy at home, taking public transport, reducing meat consumption, and even just repairing our stuff instead of buying new ones.