For millions of years, the global climate has fluctuated. However, the trajectory of climate change is being drastically altered by humanity. Our accelerated economic development is having a serious impact on the world’s climate.
These days, it seems like climate change is on the tip of everyone’s tongues, from those champion our need to act to those who vehemently deny that the climate is changing at all. According to the Consensus Project, an initiative that uses peer-reviewed science to measure the consensus on whether humans cause global warming, 97 per cent of scientists agree: global warming is man made and is the result of of our reliance upon fossil fuels such as oil, coal and gas.
The Drivers of a Changing Climate
In the last few millenia, the most important drivers of climate change have been tectonic shifts of the continents, and fluctuation in ocean circulation and placement of mountain ranges across the globe. However, since the time of the industrial revolution, human activity has greatly increased the rate of climate change, to levels of unprecedented warming and atmospheric disruptions.
There are of course many examples throughout history of extreme and abrupt changes in climate. One example is the PETM (Paleocene-Eocene- Thermal Maximum) which took place around 55 million years ago. During this time, the temperature rose by about five degrees as a result of around 2,000 Gigatonnes of CO2 being naturally released into the atmosphere over a period of about 10,000 years. In the anthropocene era, human activity will most likely achieve this same result within a period of a few hundred years.
This rapid alteration in climate conditions is mostly due to humanity’s alteration of natural atmospheric conditions. Changes in the composition of the atmosphere, where once were caused by things like volcanic activity, are now driven by humans’ burning of carbon-rich materials such as oil, coal, and natural gas. The emissions from this fossil fuel consumption disrupts the natural system and increases the proportion of CO2 in the air faster than natural processes can handle. In essence, the natural, ecological scale is tipped and has thrown the climate out of balance.
While it’s true that climate change is a natural occurence, today however, the rate at which the climate is changing means we require a shift in focus: not just looking at how and why the climate is changing, but how can we act to tackle it. For all intents and purposes, climate change as it exists today is a man-made phenomena.
Greenhouse Gases Explained
The greenhouse gases in the atmosphere play a decisive role in the earth’s temperature. The most important are:
- H2O (Water Vapour)
- CO2 (Carbon Dioxide)
- CH4 (Methane)
- N20 (Nitrous Oxide)
- Tropospheric O3 (a key constituent of some areas of stratosphere known as the ozone layer, it absorbs harmful UV-radiation)
Damage is caused principally through the production of greenhouse gases, so called because they have an effect similar to the glass roof of a greenhouse. They allow the sun’s rays to penetrate the atmosphere so as to heat up the earth, but they perform an almost shield-like effect, preventing part of the energy from being radiated back into space. As a result, the earth and its atmosphere are slowly heating up. This is the famous greenhouse effect.
Without the greenhouse effect, the average temperature would hover around minus 18 degrees. The key here is differentiating between the natural greenhouse effect, triggered by naturally occurring greenhouse gases in the atmosphere, and the anthropogenic, man-made, additional greenhouse effect which enhances the natural greenhouse effect and encourages current global warming.
The latter occurs when additional greenhouse gases are released into the atmosphere, primarily via the following ways:
- Burning fossil fuels like oil, gas, and coal
- Deforestation or soil extraction (more info can be found here Forests – Our Green Lungs)
- Loss of soils, permafrost, and wetlands releases stored CO2 and methane (and prevents reabsorption)
- Waste disposal, animal husbandry and rice cultivation release methane
- Fertilisers consisting predominately of nitrogen
- Man-made chlorofluorocarbons (CFCs) and other cooling, quenching and propellant gases
A Brief History of Climate Science
The human impact on the climate has been hypothesised, analysed and discussed since as far back as ancient Greece, when Theophrastus, a student of Aristotle, indicated how human activities in the local area (such as draining marshes and chopping down trees) had either a cooling or warming effect on the climate. Various scientists toyed with the the effect of carbon dioxide on the planet’s temperature, an area of research that started to slowly scale up once the industrial revolution went into full swing. In 1896, Swedish scientist Svante Arrhenius published his theory that the burning of coal, which released carbon dioxide into the air, caused a ”greenhouse effect” that could lead to an increase in temperature over a number of centuries.
Arrhenius’ theory was largely decried as implausible and it wasn’t until mid-way through the 20th century that the idea of humans influencing global temperature really started to gain traction. In the 1950s, US scientist Charles David Keeling developed techniques that could accurately measure carbon dioxide in the air. Dr. Keeling gleaned readings that showed that the amount of carbon dioxide in the air was rising year after year with tests later showing that this increase was a result of fossil fuels combusting. Dr. Keeling’s research became, and remains to this day, the touchstone for modern climate science.
How Can We Forecast Climate Change?
As we can see, thanks to daily weather forecasts, changes in the weather can be predicted a few days in advance. Does this also apply to the climate? In a way, yes. As mentioned previously, talking about the climate leads towards discussions about average temperatures over long periods of time. In that sense, we need to think about how to change these averages. Since it is now well and truly established that greenhouse gases play a central role in climate change, one way that scientists measure climate change is by looking at these gases and their effect in raising average global temperatures.
Since the Copenhagen Climate Conference in 2009, and affirmed in the 2015 Paris Climate Accord, 2 degrees celsius (above pre-industrial levels) has been widely accepted among policy makers as the benchmark for allotted global average temperature increase. However, scientists say this target doesn’t go far enough. James Hansen, today one of the world’s most prominent climate scientist, said that the 2 degree target “is actually a prescription for long-term disaster”. Bill McKibben, an American writer who authored the first book on climate change for the general public, suggested the benchmark was a suicide pact of political realism. It doesn’t take much digging into current temperature trajectories related to climate outcomes to understand why.
From the time global measurements first became possible, 2017 marked the second warmest year in modern history according to NASA scientists. This warming hasn’t occurred gradually. Of the 0.8 degree celsius increase in average global temperatures since the industrial revolution, two-thirds of this warming has occurred since 1975. This change is at a rate of about o.15-o.20 degrees celsius per decade. Though discourse revolves around deceptively small upticks in temperature, current projectories promise catastrophic implications for the future of the planet. Already, low-lying islands in the Pacific Ocean are purchasing land in neighbouring nations due to rising tides. As oceans absorb much of the excess carbon dioxide from the air, they have become 30 percent more acidic, effectively sickening the Great Barrier Reef and its ecosystems, and threatening food security in coastal communities around the globe. The world is almost halfway through its emissions budget, and anthropogenic climate change is already changing the landscape of the only assemblage of life known in the universe.
What Happens as the Climate Changes?
The warming of the earth has many consequences:
- Polarcaps and glaciers melt
- Sea level rise
- Biodiversity is threatened (due to loss of habitat and compromised food sources)
- Extreme weather patterns occur more frequently
This change to our ecosystem also present some difficult effects for humanity, namely:
Food supply: productive agricultural areas will shift geographically and the productivity of grazing land could drop
Water supply: Higher rates of evaporation and increased intensity and duration of droughts will elevate water scarcity in some parts of the world
Climate refugees: exacerbated droughts, soil erosion, desertification and natural disasters can all lead to population displacement and human migration. (Find out more via our Knowledge article on Environmental Refugees)
Even if there was an abrupt end to greenhouse emissions, the climate would still change and global warming would still progress by about 0.8 degrees. The reason behind this lies in the large amount of greehouse gases that exist in the atmosphere. The climate reacts relatively slowly meaning it would continue to change.
What Can Be Done to Combat Climate Change?
The challenge is limiting the extent of climate change so that consequences of it remain within a manageable framework that still allows us to survive on this planet. Some of the proposed solutions centre on the need to reduce and stop the level of greenhouse gases being released into the atmosphere and, where possible, undo some of the existing damage. A functioning, regulated emissions trading scheme can be an effective instrument to reduce greenhouse gas emissions.
Long-term, the planet needs to shift from using fossil fuels to renewable forms of energy. At the same time, we must find ways to adapt to any changes that occur through better coastal protection, more efficient construction techniques and intelligently-designed cities.
This speech from US climate change activist Bill McKibben gives a very good overview of the problem of climate change, its correlation to the fossil fuel industry as well as possible solutions:
Ultimately, combatting the climate change and adpating to its effects is up to all of us. Conserving energy, recycling, buying regional produce and smartly using water are small things we can all that can have a big (positive) impact. Check out our Act Now article 12 Things you can do on climate change for inspiration.
Translated in part from the article on our German site Der Klimawandel – Eine Annäherung by Ariane Kujau. Updated February 2018 by Alex Mitchell.