What causes the climate change?

Threatening waves of heat, which drown coastal cities, and tens of thousands of displaced refugees … These words can very well describe a scene from the last horror film. But they also describe the nightmare scenario that we humans will face decades from now if we continue to fail to address the threat of climate change.

This term, climate change (which is short for anthropogenic climate change), refers to the full set of characteristics: temperature; precipitation; pressure systems, wind patterns; and ocean currents, which change both locally and regionally due to human influences. It is closely related to global warming, which describes the general upward trend in global temperatures that we observe as part of climate change.

Climate change has the potential to make the Earth unrecognizable from what any human being has ever experienced. These changes will have an immense impact on ecosystem services, global economies, and our own quality of life. Yet, while much is said about these risks, there is too little action to address the root causes.

Some of the inaction can be attributed to “climate change” and “the future” often used in the same sentence, giving politicians and industries the false impression that we can tackle climate change once sufficient economic growth is achieved. The reality, however, couldn’t be further from the truth, as we are already seeing today the signs of the changes, including near-annual crop failures, record high temperatures, and record-strength coastal storms.

Fortunately, as the understanding grows that our businesses are creating a global crisis of epic proportions, the impacts of climate change are now hotly debated in the halls of government and business. Politicians, media and others are also increasingly replacing ‘climate change’ with livelier language, such as ‘climate crisis’ and ‘climate emergency’. Hopefully, this will encourage even more governments and industries to come the table and cooperate like never before to tackle the main drivers of climate change.

Solving this global crisis requires a multi-pronged international approach that should include ecosystem protection and restoration, direct species management, and legislative action. But before considering the solutions, we will first explore why climate change is happening and how it will affect biodiversity in the decades to come.

Examples of Climate Change

Widespread drought

East Africa experienced the worst drought in 60 years, from mid-2011 to mid-2012. More than 250,000 people died; nearly 10 million more needed humanitarian assistance. The greater intensity of similar droughts in 2016 is directly attributable to climate change.

Sea level rise

Coastal flooding disrupts local lives and economies in Ghana, Nigeria and Benin almost every year. Coastal erosion has damaged commercial properties in The Gambia and Senegal, while the coast has receded by 35 m in parts of Togo.

Early spring activity

Flowering dates for several plants, including apple and pear trees grown commercially in South Africa, are now between 1.6 and 4.2 days earlier every ten years than 35 years ago.

Changes in species ranges

Malaria has recently appeared in the highlands of Ethiopia, Kenya, Rwanda, and Burundi, in areas where it did not previously exist.

Declining wildlife population

Report rates of some endemic bird species in the Cape Floristic Region have declined by more than 30% over the past 15 years.

What Causes Climate Change?

The climate change we are experiencing today is caused by human activities that increase greenhouse gas concentrations in Earth’s atmosphere. Although we mainly hear about greenhouse gases in the context of their contribution to climate change, they are in fact essential to life on Earth.

Greenhouse gases are essential for life on Earth. But too many of them are causing the Earth to heat up too quickly, leading to climate change.

Consider for a moment the critical role of carbon dioxide (CO2) in photosynthesis and the role of water vapor in the formation of rain. Both of these gases are greenhouse gases. Greenhouse gases earn their name because they function much like the glass covering a greenhouse. They allow sunlight to easily pass through the atmosphere but trap the reflected thermal energy so that it remains close to the earth’s surface. This greenhouse effect allows all organisms on Earth, even us humans, to thrive.

Without greenhouse gases, temperatures would drop and our planet would be too cold to support life. However, even high concentrations of greenhouse gases can be harmful. Think of greenhouse gases for a moment as “blankets” covering the earth’s surface: more “blankets” will trap more heat, leading to higher temperatures.

This is exactly what is happening today: human activities have currently increased the concentrations of greenhouse gases in the atmosphere so much, and at such a rapid rate, the Earth is warming too quickly for biodiversity to adapt to the change.

At present, the single biggest cause of increased greenhouse gas concentrations is the burning of fossil fuels. Since the industrial revolution, around 200-250 years ago, humans have become very dependent on energy captured in these fuels (coal, oil, and natural gas) for activities such as transportation, heating, generation, and power generation.

Fossil fuels contain a high percentage of carbon, so when burned, that carbon is released into the atmosphere, usually as CO2. As a result, since human populations began to explode and use fossil fuels at higher rates, the greenhouse effect has been greatly amplified. Although the burning of fossil fuels is currently the main global driver of climate change, the largest contributor to it.

Africa is destroying carbon sinks, such as rainforests and peatlands. The destruction of these ecosystems contributes to increased atmospheric CO2 concentrations directly through the burning of carbon-emitting vegetation and indirectly by the loss of vegetation which, if still alive, would remove CO2 from the atmosphere.

The contribution of ecosystem loss to climate change is substantial: 13% of today’s global carbon emissions could be due to tropical deforestation. This impact is much stronger in Africa, where deforestation accounts for 35% of the overall impacts of climate change in the region. In comparison, the energy and agriculture sectors in Africa contribute 30% and 24% respectively.

The link between human-induced climate change and atmospheric CO2 concentrations was first highlighted in the late 19th century. However, it was not until the mid-1950s that scientists started to raise concerns about increasing CO2 concentrations in the atmosphere. By the 1980s, as global annual mean temperatures started to rise, consensus about climate change linked to CO2 began to spread among the broader public.

Yet concrete steps to curb CO2 emissions would only be initiated decades later. In the meantime, CO2 emissions continue to accelerate: more than 37 billion tonnes of carbon, a new record, were released into the atmosphere in 2018. To put it in another way, during 2018, humans released on average over 100 million tonnes of CO2 into the atmosphere every day.

The second-most important greenhouse gas that drives climate change is methane (CH4). Methane is a natural by-product emitted from decaying organic matter, most notably from wetlands that inhibit the speed of decomposition. These important ecosystem processes release methane into the atmosphere, albeit in relatively low concentrations.

However, human activities have boosted methane emissions significantly over the past few centuries, through wasted food decaying at landfills, leaks from natural gas wells, an increase of industrial-scale cattle and dairy farms, and large-scale destruction of swamps and peatlands.

Warmer temperatures also result in the drying of wetlands and peatlands; this drying speeds up the decomposition of organic material, which increases the rate of methane release. Methane currently constitutes16% of all global greenhouse gas emissions released by humans. This may not seem to be a major contribution; however, methane is 72 times more effective than CO2 in trapping radiation over a 20-year period, so even small increases in atmospheric methane can have dramatic effects.

The third important greenhouse gas that drives climate change is nitrous oxide(N2O), also known as laughing gas. Nitrous oxide is a by-product of synthetic fertilizers used in agriculture, burning of fossil fuels, and several industrial processes, and accounts for 6% of all human-caused greenhouse emissions. However, it is even more potent than methane and stays in the atmosphere for about 114 years, so the impact of one tonne of N2O is equivalent to 310 tonnes of CO2 over 100 years.