By Gabriel Andre – Art in Tanzania internship
Welcome to part 1.2 in our new climate change blog series.
What are the main consequences of climate change and the risks to our survival?
The first consequence of climate change is obviously the rise in temperature and the harmful consequences of heat on biodiversity. But why do we keep hearing that we must not exceed the “2 degrees more” of the Paris Agreement by 2100?
Þ Temperature rise and disruption of the water cycle
Indeed, the storage capacity of water in the atmosphere varies according to its temperature. As the temperature increases, the storage capacity increases. As the temperature rises, evaporation is prevalent, and the amount of water stored as water vapor increases. As a result, rainfall is more abundant and there is an increase in the frequency and intensity of heavy precipitation events (especially in mid-latitudes and humid tropics). Warmer air can also contain more water vapor and therefore intensifies extreme phenomena’s such as cyclones, hurricanes, and typhoons. There is no need to recall the human tragedies caused by hurricanes Sandy (2012), Irma (2017) or Hurricane Harvey (2017).
Þ Melting ice zones
Global warming leads to the melting of ice zones (glaciers, ice caps, ice pack) with different consequences. Melting glaciers impact freshwater reserves because by melting too quickly, they no longer fulfil their role as reservoirs that gradually release freshwater at steady intervals. Freshwater is drinkable and is a vital need for animals and humans on a daily basis. Today, the demand for water exceeds the quantity available, which is already a major geopolitical issue in many dry regions of the world. In addition, the melting of these glaciers releases fresh water which then flows into rivers, seas, and oceans, causing water levels to rise. The melting of the ice sheets, huge areas of ice resting on land whose height can reach several thousand meters, would be devastating if they were to melt entirely.
On our planet, there are only two ice sheets:
- The northern part of Greenland, which has existed for 3 million years
- The southern part of Antarctica, which is the largest, and has exist for 30 million years. Given the thousands of meters of thickness of the ice sheets, their complete melting would raise the sea level by 7 meters for Greenland, 54 meters for Antarctica, consequently causing the disappearance of many islands (such as the Maldives) and the relocation of a large part of the coastal population.
Þ Our forests are dying’s
As we have seen with the carbon cycle, forests today are a very important for sequestering carbon. As living matter, flora is composed of carbon and thanks to photosynthesis, it absorbs atmospheric CO₂ to transform it into oxygen. Conversely, when the forest dies or in the event of deforestation, the decomposition of plants leads to the emission of CO₂. The same is true when fires ravage forests: combustion releases into the atmosphere all the CO₂ that was then stored and stabilized.
With climate change, we are witnessing:
- a warming of the air and soil temperature, destabilizing ecosystems, and biodiversity,
- periods of drought and flooding that can deplete soils and kill the biosphere,
- a significant increase in fire outbreaks and intensity.
These three phenomena’s, which are consequences of climate change, lead to the decline of plants. Those that survive will have a poorer capacity to absorb CO₂ and those that die will decompose releasing CO₂. Thus, the concentration of GHGs in the atmosphere increases, fueling global warming which in turn feeds the three causes listed above. Between the Australian forests going up in smoke in the summer of 2019, and President Bolsonaro’s efforts to deforest the Amazon as quickly as possible, we are not talking about a hypothetical situation. The latter said, in opposition to pressure from European countries, to act to slow the fires in the Amazon “Brazil owes no debt to the planet in terms of environmental preservation”, he said during a conference in Santiago Chile on May 23rd of 2019.
Þ The two climate time bombs
Permafrost refers to ground that is permanently frozen, i.e., at a temperature that has never been above 0 for at least two years. Permafrost is found on about 20% of the planet’s surface, notably in Greenland, Alaska, Canada and Russia. It is even found in France, in the Alps.
The huge problem with permafrost is that it contains elements that have been locked in the ice for thousands of years. To take an image, permafrost is like a huge freezer. If you leave the freezer door open, your pizza thaws, your ice cream melts and microbes feed on these organic elements. Similarly, as the permafrost melts, it releases organic matter which, when subjected to the activity of microbes, produces CO₂ in the presence of oxygen or methane in an oxygen-free environment. These GHGs would then enter the atmosphere and accelerate global warming.
The potential for releasing GHGs from permafrost is colossal: we are talking about 1500 Gt, i.e., twice the amount of GHGs already present in the atmosphere. This would triple the concentration! Just imagine the additional greenhouse effect that would be generated. In this sense, the melting of a large part of the permafrost constitutes one of the two “climate bombs” from which it would probably be impossible to recover. Another important consequence is that permafrost also contains diseases that have been dormant for hundreds or thousands of years. If the permafrost melts, it could release them and create major health crises.
For example, in 2016, an Anthrax outbreak killed several humans and over 2,300 reindeer in Siberia. The disease had disappeared for more than 75 years in the region.
It reappeared with the melting of permafrost, which kept the corpse of reindeer that had died of the disease (and thus its deadly bacteria) frozen. Anthrax can be treated with the antibiotics; however, this would not necessarily be the case for all the other viruses that we do not know or do not know how to treat. The risk of epidemics or outbreaks of disease is very high. The risk of epidemics or pandemics much worse the Covid 19 is also very real consequence of climate change.
Another potential ‘climate bomb’ is methane hydrate. These are methane molecules trapped in ice. They are found in large quantities:
- Under permafrost
- At the bottom of the oceans, in ocean sediments.
For the moment, this methane is stored in these reservoirs in a stable manner. It’s difficult to estimate the exact quantities, but we are talking about 10,000 Gt, which is 7 times more than all the GHGs contained in the permafrost, and therefore 21 times more than all the GHGs currently present in the atmosphere!
Unfortunately, if current warming exceeds the famous 2-degree mark, these molecules could become unstable. As the permafrost melts or the oceans warm up, methane hydrate would come into contact with higher temperatures. The unstable probability of these molecules becomes significant with a 2 degree rise in temperature. In this case, the molecules can dissociate, and the methane can escape directly into the atmosphere. Given the titanic volume of methane we are talking about, it is easy to understand the devastating consequences for global warming and life on Earth.
There are many other devastating effects caused by global warming, such as the acidification of our oceans, possibly causing the disappearance of its aquatic fauna and flora; modified ocean currents, reducing the capture of CO2; or the Albedo effect, which is the mechanism of absorption and reflection of light energy that will be less and less effective because of the ice melting. We therefore understand that it is imperative to act quickly for our survival and to avoid scenarios such as the melting of the permafrost or islands like the Maldives which is being buried by the rising waters. As climate scientist and Nobel Peace Prize winner Jean Jouzel says, “Global warming, as it would be if nothing is done, is another world.” It is a world where, according to the UN, there will be at least 150 million climate refugees. It is a world where southern Europe would resemble to Sahara with temperatures approaching 50 degrees in the summer in France. It is a world where by 2070, 1 billion people will be living in areas where almost every day of the year, outdoor conditions will be lethal.
But if a country like France would be like the Sahara in the summer, what can a country like Tanzania, which already experiences temperatures of over 40 degrees from November to March, expect? What would be the impact of global warming on a population where more than 80% of the people live only on agriculture and are totally dependent on the climate?