Climate Change 101

Climate Change 101

by Juliana Ariffin

The topic of climate change has never been hotter, but with all the predictions, trending articles and heated debates by politicians claiming ‘aye’ or ‘nay’ about its existence and effects, it can be hard to get one’s head around the topic. So, in this article, we’ll get back to basics and review what the fuss is all about – with the key points that everyone should know about climate change.

What is ‘climate change’?

The term ‘climate change’ refers to changes in the normal patterns of global or regional climates. However, the way the term is used nowadays normally refers to the effects of human activity on Earth’s climate, primarily in causing the heating of the Earth’s surface temperature, which is termed global warming.

Is climate change really happening?

Over 97% of publications by climate scientists in peer-reviewed scientific journals agree that climate change is happening [1].  But due to the denial of a handful of scientists and the influence of politicians and big companies, this claim has been subject to much debate.

Even so, data from four independent and international scientific institutions shows that the earth has been undergoing rapid warming in recent decades, with the most recent decade the warmest on record (Figure 1).

Figure 1: Temperature data from 1880 to 2020 from four international science institutions. Data sources: NASA’s Goddard Institute for Space Studies, NOAA National Climatic Data Center, Met Office Hadley Centre/Climatic Research Unit and the Japanese Meteorological Agency. (Image from NASA [2])

Are humans responsible for it?

Man-made climate change is widely agreed by scientists to be caused by human activities that exacerbate the ‘greenhouse effect’—the entrapment of heat by atmospheric gases, leading to heightened warming of the Earth’s surface temperature (Figure 2). Once released, these gases persist in the atmosphere as they are long-lived and do not react to temperature changes like water vapour does. Thus, they continue to block more heat as they collect in the atmosphere. Among these gases are carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs). Water vapour is also classified as a greenhouse gas, but in contrast to the other gases, it reacts to changes in climate and is useful as a feedback mechanism, increasing as Earth becomes warmer. However, with increased warmth, water vapour begins to precipitate and form clouds. This results in changing weather patterns with some regions becoming wetter and some drier.

The global temperature has risen by more than 1.5oF (~0.8oC) since the late 1800s [3]  (Figure 3). This phenomenon does not correlate with natural causes but does correlate with human emissions of greenhouse gasses and other activities that affect the reflectivity of Earth’s surface, such as deforestation, agriculture and urban development [4].

Figure 2: Human Influence on the Greenhouse Effect. (Image from the National Climate Assessment [4])

Figure 3: Maps showing temperatures across the world in the 1880s (left) and the 1980s (right). Blue colours represent cooler temperatures in comparison to averaged temperatures from 1951 to 1980, and red represents warmer temperatures. Two-thirds of the warming occurred since 1975 at an estimated rate of 0.3oF-0.4oF per decade. (Image from NASA [5])

The Tipping Point

We are already experiencing signs of climate change. This includes abnormal weather patterns and fluctuations, rising sea levels, changes in animal territories, early flowering or fruiting of plants, the melting of mountain glaciers and the retreat of polar ice sheets.

However, this is still the calm before the storm. Scientists warn that once the Earth has heated to a point of no return it may reach a tipping point beyond which the Earth’s temperature will stabilise into an irreversible heating trend. This is associated with the release of methane from frozen deposits (methane hydrates), the conversion of heat sinks into heat absorbers (e.g. heat reflective Arctic sea ice melts, becoming dark ocean water that absorbs heat), the reduction of forests due to their conversion into grasslands and savannahs or forest fires, and ocean acidification leading to changes in the marine ecosystem (Figure 4).

Figure 4: Map of climate tipping elements, adjusted from Lenton et al., (2008), based on further analysis by T.M. Lenton, reported in Richardson et al., (2011). (Image from Peter Carter Climate Emergency Institute [6])

What can we do?

The way we live now will change drastically if nothing is done to halt or even reverse climate change. Among the predicted changes are that food would become more expensive as animals and plants are threatened by changing weather, loss of habitats and loss of arable land. The rising sea levels would affect marine flora and fauna and engulf coastal areas and low-lying nations such as Kiribati and the Maldives as well as the historic city of Venice. Due to this, the rising food costs and erratic weather patterns that lead to natural disasters, we might expect to see an increase in what is being termed ‘climate refugees’.

The complexity of the Earth’s climate and the far-reaching impacts of climate change may make one wonder what a single individual can do to avert disaster. But as individuals, we still have a lot of power and ability to exert our influence if we:

Choose to eat less beef

Cattle rearing uses up a lot of water and massive amounts of land to grow feed for the animals. The cattle themselves are a big source of methane from the gases they produce by burping and from their manure. This results in a big impact on greenhouse gas composition and a lot of wastage of resources (Figure 5). If we all chose to consume 40% less beef and dairy products than we currently do, it would make a big difference on the Earth’s resources and environment (Figure 6).

Figure 5: The Environmental Impact of beef consumption (Image source: The World Resources Institute [7])

Figure 6: Impact of reducing consumption of beef and dairy products. (Image source: The World Resources Institute [7])

Consume climate-friendly food, consumables and energy

We need to educate ourselves on what foods, consumables and energy are available to us that are climate-friendly and that still suit our needs. Small changes in behaviour such as reusing plastic bags (or using biodegradable plastics); donating or recycling used items (e.g. clothes, toys, electronics) that will just end up in landfills and pollute the environment if thrown away; and choosing to use less energy (e.g. turn off your lights, carpool, walk) or to obtain energy from renewable sources (e.g. solar) can make a big difference if practiced often and by many people.

Besides choosing not to waste, it’s important to be selective when choosing to spend your money. Be aware that some of the food-products or consumables you buy may have been made from environmentally unfriendly material or through environmentally unfriendly means. Most of us who live in Southeast Asia are troubled by the haze from the forest fires in Indonesia which cause severe health effects, forest depletion and endangers the indigenous animals of the region. But how many are aware that every time you buy a pack of Nissin instant noodles, a can of Pepsi, a bar of Kraft cheddar cheese, or eat a healthy serving of Quaker Oats, you are putting money into the pockets of Nissin, PepsiCo and Kraft Heinz, some of the big companies that irresponsibly profit from the palm oil obtained from palm plantations grown on land cleared by the forest fires in Indonesia? [8]

Vote for authorities that agree to avert climate change and hold them responsible

To this date, 112 countries have formally consented to uphold the recent Paris Agreement held on 12 December 2015, which is meant to come into effect the 4th of November 2016 [9]. This agreement, which aims to reduce greenhouse gas emissions via fossil fuel usage and to keep global temperatures from rising more than 2oC (3.6oF) by 2100 is a great achievement, showing awareness and initiative for a united global effort to combat the dangers of climate change [10]. However, there are no legal requirements or ramifications of not upholding the agreement, and the success of the agreement lies in global peer pressure and the actions of the individual governments that submitted their ratification.

We may think that we have little say or responsibility as individuals and that it’s up to the higher ups and global organisations to make and enforce policies that will benefit us. But all countries are made up of single individuals who can make their opinions known by voting, choosing their individual day-to-day practices, by vocal or written expression, or by choosing how to spend their money. Hence, if you wish to leave this world a better place than we found it and allow future generations to experience nature’s beauty just as we currently can, don’t just stand by. Take action and be the change you wish to see in the world!

Further readings

1)     Good basic Q&A about climate change:

2)     Before the Flood (Documentary by Leonardo DiCaprio)

3)     NASA: Global Climate Change:


[1] J. Cook, et al, “Consensus on consensus: a synthesis of consensus estimates on human-caused global warming,” Environmental Research Letters Vol. 11 No. 4, (13 April 2016); DOI:10.1088/1748-9326/11/4/048002

[2] NASA: Scientific Consensus: Earth’s climate is warming. Link:

[3] Intergovernmental Panel on Climate Change (IPCC): Climate Change 2013: The Physical Science Basis2013). Contribution of Working Groups I, II and III to the Fourth Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Link:

[4] U.S. Global Change Research Program (USGCRP) (2014). Melillo, Jerry M., Terese (T.C.) Richmond, and Gary W. Yohe, Eds. Climate Change Impacts in the United States: The Third National Climate Assessment. Link:

[5] NASA: Global Temperature. Link:

[6] Climate Emergency Institute: Tipping Points. Link:  [7]The World Resources Institute – Sustainable diets: What you need to know in 12 charts, by Janet Ranganathan and Richard Waite, April 20, 2016. Link:

[8] Rainforest Action Network – Conflict Palm Oil. Link:

[9] United Nations Framwork Convention on Climate Change – Paris Agreement – Status of Ratification. Link:

[10] – What to know about the historic ‘Paris Agreement’ on Climate Change. Link:

About the author

JULIANA ARIFFIN is a postdoctoral fellow researching liver inflammation at Beth Israel Deaconess, Medical Center, Harvard Medical School. Prior to this, she completed her PhD on  human immune responses at The Institute for Molecular Biosciences, The University of Queensland. In her spare time she reads and writes fiction, dabbles in photography and considers genetically engineering a zombie propagating virus to repopulate the earth. Check out Juliana’s Scientific Malaysian profile at