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The effects of both natural and human-induced climate change are profound. Climate change places tremendous stress on our environment, economic, social and political systems. This article explains how the rising temperature affects the environment and our lives, particularly from the perspective of social and economic equality.
Also read: Global-Scale Pollution (Part 2): How Does Global Warming Occur?
Coral Bleaching
We now know that global warming means the temperature near the Earth's surface gets warmer than before. Oceans have absorbed over 90% of our extra heat over the last 50 years. This makes sea water gets warmer as well. When water is too warm, corals will expel the algae living in their tissues, causing the coral to turn completely white. This phenomenon is called coral bleaching.
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Bleaching slows their growth and makes them vulnerable to algae, disease, and death. So warmer sea water is the first reason for coral bleaching. The second reason is more acidic seawater. But how can sea water gets more acidic?
The answer is the extra carbon dioxide we emit in the atmosphere. The oceans are doing their best to absorb that excess carbon, making the ocean water more acidic. Actually, the sea water is still slightly alkaline, but less than it was. Corals find it more difficult to build their structures in increasingly acidic waters.
Consequently, when we dive, we can hardly see majestic coral reefs, brimming with multicoloured fish of all shapes and sizes. The Australian Great Barrier Reef is now the largest aquatic cemetery in the world. Half of the world's coral reefs are already dead. Sadly, coral reefs worldwide could be mostly wiped out by 2050 or soon after.
Why are coral reefs so important to us?
Coral reefs contain the most diverse ecosystems on the planet. As oceans have absorbed carbon dioxide, the water has become more acidic, and the pH levels are now so hostile to marine life. On the one hand, a few countries have responded by banning fishing, even in international waters, to preserve the few fish left. On the other hand, many insist that the few fish left could be enjoyed while they last.
Coral reefs also protect coastlines from the damaging effects of wave action and tropical storms. They provide habitats and shelter for many marine organisms. They also give opportunities for tourism and recreation.
Melting of Sea Ice
Sea ice is frozen salty ocean water that floats on the ocean surfaces. Sea ice forms in both the Arctic and the Antarctic and can be labelled as ice shelves (mass of ice that floats on the ocean but remains attached to the coast). Sea ice forms in winter and melts in summer but does not completely disappear. Roughly, 15% of the world's oceans are covered by sea ice during a portion of the year. On average, sea ice covers up to 25 million square kilometres, the same size as the North American continent.
Arctic sea ice is disappearing at almost 13% per decade due to long-term climate change. Over the past 30 years, the oldest and thickest ice in the Arctic has declined by incredibly 95%. Scientists believe that sometime this century, the Arctic Ocean will be entirely ice-free during the summer for the first time in about a million years.
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The Great Melting is an accelerant of further global warming. White polar ice reflects incoming sunlight back to space, regulating temperatures worldwide. But as the ice disappears, darker water is exposed. This darker water absorbs more heat, warming the air and causing more sea ice to melt. Consequently, the mass of water is expanded, and sea levels are pushed higher. Over several years, this positive climate feedback loop can influence the global climate.
What are the consequences of sea ice melting?
When sea ice melts, there is no change in sea level. Because sea ice is already floating in the ocean, it displaces its own weight, based on Archimedes' principle. However, melting polar ice will have disastrous effects on some ecosystems and species, such as polar bears, arctic seals, and penguins.
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Melting of Land Ice
Glaciers (mass of ice that moves slowly over land) are land ice. Land ice can be labelled as ice sheets (thick layer of glacial ice covering an extensive tract of land for a long period of time). Ice sheets contain about 99% of the freshwater on Earth and are sometimes called continental glaciers.
Ice sheets become ice shelves as they extend to the coast and over the ocean. Put differently, an ice shelf is a floating extension of land ice (for example, the Antarctic continent is surrounded by ice shelves). When chunks of ice shelves break off and fall into the ocean, they become icebergs. Land ice covers approximately 15 square kilometres, roughly equivalent to 10% of the Earth's land surface area.
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| Melting glacier in Greenland. Source: wirestock/elements.envato.com |
What are the consequences of land ice melting?
As mentioned above, the melting of floating sea ice does not cause sea levels to rise. But when ice sheets on land melt, that adds a deluge of fresh water into the oceans. Ice shelves act as a reinforcement, preventing glacial ice from reaching the ocean. Once the barrier is gone, glacial ice melt entering the ocean would increase the sea level.
The sea levels have risen more than 20 centimetres, leading to major salt intrusion in many aquifers, worsening storm surges, and existential threats to low-lying islands. If humans continue business as usual, some climate scientists believe that it is likely that sea levels will rise to tens of feet in the next century. Large portions of major cities and islands are projected to be underwater, and much larger parts would be susceptible to coastal flooding and storm surge events. Miami, Florida, is already facing the effects of sea level rise regularly and has begun to raise roads to address the problem.
Greenland and Antarctica combined contain about 75% of the world's freshwater, enough to raise the sea level by over 75 metres if all the ice were restored to the oceans. To put that into perspective, based on the US National Science Foundation simulations, a 1-metre level sea rise would displace 100 million people who live along coastal lines.
Mountain glaciers worldwide, from the Himalayas to the Alps and to the Andes, are also disappearing rapidly. Little snow turns to ice atop mountains in the winter, so there is no more gradual melting in spring and summer. In the short term, increased meltwater flow will fill rivers and improve crop irrigation. Certain cities depend upon glaciers as their primary water source. But once the glaciers are gone, these cities will face a water crisis with no immediate solution.
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| Melting of mountain glacier in Iceland. Source: kegfire/elements.envato.com |
Permafrost (soil frozen for centuries in cold climates under a layer of topsoil) in Alaska and Siberia appears to be melting too. There is an even bigger problem associated with the melting permafrost.
Permafrost contains organic material that froze before decaying, releasing centuries of stored carbon dioxide and methane into the atmosphere when it thaws. Large permafrost regions in the polar north and south are expected to become significant sources of greenhouse gas emissions in the next 60 years. It is estimated that they will remain that way for over 300 years.
Heatwaves, Droughts and Flooding
Global warming increases drought events by shifting precipitation patterns and rising air temperatures. Extreme weather events such as prolonged heat waves are predicted to continue increasing in intensity and frequency. As devastating as rising sea levels have been, droughts and heatwaves inland have created a special hell.
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| Drought in Spain. Source: recstockfootage/elements.envato.com |
In June 2015, the temperature in Karachi, Pakistan, soared to 45℃, killing 2,500 people. Japanese population have never adapted themselves to scorching temperatures. When the temperature reached 41℃ for many days in the mid of July 2018, 22,000 people were hospitalised, and 80 lost their lives. Those living in Paris have to endure summer temperatures that regularly rise to 44℃.
Vast regions have succumbed to severe aridification, sometimes followed by desertification and wildlife there has become a distant memory. These places can hardly support human life; their aquifers have dried up. Cities like Marrakech in Morocco and Volgograd in Russia are on the verge of becoming deserts.
Hong Kong, Barcelona, Abu Dhabi and many others have been desalinating seawater for years. Approximately 2.7 billion people experience water scarcity yearly, and potable water is becoming a globally scarce and valuable resource.
While some regions experience more severe droughts, others see increased rainfall and large-scale flooding. The 2016 Indian flood is one of the world's worst flood disasters. It killed between 1000-8000 people.
Climate change will make it harder to grow food in some places. Climate zones have shifted, so some new areas like Alaska in the Arctic have become available for agriculture, while others like Mexico and California have dried up. Still, others are unstable because of the extreme heat, never mind flooding, wildfires, and hurricanes. Generally, this makes the food supply highly unpredictable.
More people are starving than ever before. Roughly 20 million people have been facing hunger across eight countries in West Africa. A combination of failed crops, insect plague, conflict, and extreme drought collectively caused the ensuing famine, considered one of the worst on the planet in recent years.
Hurricanes and Tropical Storms
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| Hurricane Ian in Florida in September 2022. Source: bilanol/elements.envato.com |
More moisture in the air and higher sea surface temperatures have caused a surge in extreme hurricanes and tropical storms. The frequency of hurricanes may not increase, but intense hurricanes are increasing. Coastal cities in Bangladesh, the US and elsewhere have suffered brutal infrastructure destruction and extreme flooding, killing many thousands and displacing millions.
One of the deadliest Atlantic hurricanes in the US was Hurricane Maria, that hit Puerto Rico in 2017. The maximum sustained wind of 175 mph resulted in 90 billion dollars of damage, claiming more than 3000 human lives.
Forest Fires
Climate change leads to hotter, drier temperatures. That makes forest fires more dangerous and destructive. Due to drought conditions and record-breaking temperatures in Australia, wildfires were at unprecedented scale and intensity from September 2019 to 2020.
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The total damage and economic loss caused by the Australian wildfires during that period was 110 billion dollars. Hundreds of thousands of people were forced to evacuate. The fires killed at least 25 people and more than a billion animals in Australia. About 25 million acres of land were damaged.
The Australian map laid on top of the Google Map of Europe by Science Connecting 2020 shows how large Australia's size is compared to Europe and how large the fire-affected areas were. When forests are burnt, carbon dioxide is released into the atmosphere. This contributes to climate change, raising the risk of more large fires in the future. So the cycle will go on and on.
Warming temperatures are altering ecosystems and species ranges. In the last 50 years, the populations of mammals, birds, fish, reptiles, and amphibians have, on average, declined by 60%. Conservative projections are that if the Earth warms only 1.7℃ to 2.2℃, 20-30% of all species will be at risk of extinction by the end of the century.
Human Inequalities
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Does global warming reinforce poverty or exacerbate inequalities? The answer is yes. According to the Global Climate Risk Index of the NGO Germanwatch, eight of the ten countries most affected by extreme weather events, such as hurricanes and monsoon rains, between 1998 and 2017 were developing nations with low or lower-middle income.
Regions like Southeast Asia are very vulnerable, not only because they are often hit but because they lack the resources to deal with the impacts. Although natural disasters are not new, climate change increases their frequency and intensity, making it harder for those affected to cope with the consequences.
Climate change is a matter of life and death. Mercy Corps states three out of four impoverished people rely on agriculture and natural resources to survive. World Bank Report estimates there will be 140+ million climate refugees by 2050, but there will likely be more.
Avoiding is Cheaper than Adapting
The financial impacts of climate change are staggering. National Oceanic and Atmospheric Administration's research indicates a dramatic shift in storm amounts, intensity, and costs. 2016 and 2017 are the two highest years of financial damage in the US, with over 15 billion dollars each year.
Sir Nicholas Stern's Review, published in 2006, warned the world's governments that,
If we do nothing, the potential annual cost of climate change is 20% of global GNP (approx. 5500 billion Euros). If we do something or change our practice, the total cost of the action to counter climate change and stabilise emissions of greenhouse gases to below 550ppm is 5-20 times less than the cost of inaction.
Our way of life could lead us to a 3℃ warmer world. Hopefully, we do not reach that point, but our planning has to be with that thinking.
Continue reading: Global-Scale Pollution (Part 4): How Does Ozone Layer Depletion Differ From Global Warming?
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