NASA defines climate change as “a broad range of global phenomenon… which add heat-trapping gases to Earth’s atmosphere.” The sources are largely carbon dioxide from fossil fuels, methane from farming and cattle, and fluorocarbons used in home appliances. This results in an increase in average temperatures across the globe, and causes other changes such as rise in sea levels, shrinking of glaciers, extreme weather conditions, and shifts in blooming cycles. The American National Security Strategy (2015) views it as a political and security threat, which can contribute to “natural disasters, refugee flows, and conflicts over natural resources.” For example, the factors behind the Somalian Civil War and Syrian one were traced to “drought and famine exacerbated by climate change.”
Here is how it works in a complex manner. A historical overview by the Intergovernmental Panel on Climate Change (IPCC) states that the top of earth’s atmosphere receives huge energy during daylight, especially those areas which face the sun. A third of this is reflected back due to the clouds, small atmospheric particles called aerosols, and reflecting light-coloured landmasses like deserts and ice. To continuously balance this incoming energy, the Earth “must radiate, on an average, the same amount of energy back into space.” This happens with the continuous emission of outgoing long-wave radiation by everything on Earth. However, to achieve a zero balance, the average temperature of earth’s surface would have to be -19 degree Celsius. In reality, the figure is 14 degree Celsius.
The reason the Earth is warmer than it should be is because of the presence of natural greenhouse gases, water vapour and carbon dioxide, which act as a partial blanket for the outgoing long-wave radiation. Human activities intensify the blanketing effect, as they add to the greenhouse gases. For instance, in the industrial period since the end of the 19th century, carbon dioxide levels went up by 30% because of the use of fossil fuels and deforestation. Hence, in the past 140 years, Earth’s average temperature went up by one degree Celsius. Such global warming can then be amplified due to positive feedback loops. For example, “as rising concentrations of greenhouse gases warm Earth’s climate, snow and ice begin to melt. This melting reveals darker land and water surfaces that were beneath the snow and ice, and these darker surfaces absorb more of the Sun’s heat, causing more warming, which causes more melting, and so on, in a self-reinforcing cycle. This feedback loop, known as ‘ice-albedo feedback,’ amplifies the initial warming caused by rising levels of greenhouse gases.” In a similar vein, there can be negative feedbacks that can diminish the overall impacts. These, in turn, can easily lead to, what is dubbed as the butterfly effect.
In the 1960’s, meteorologist Edward Lorenz discovered that “very slight differences in initial conditions can produce very different forecast results. In effect, a butterfly flapping its wings in one place can, in principle, alter the subsequent weather pattern in a distant place (like a Tsunami on the Indonesian coast). At the core of this effect is chaos theory, which deals with how small changes in certain variables can cause apparent randomness in complex systems.”
This was exactly opposite of what the French mathematician, Pierre Laplace, predicted about 150 years ago. In a regid deterministic manner, he wrote, “We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all the forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.”
Future Is Here
A warmer world will raise the sea levels. Already, islands of the Solomon Islands are submerged. By 2050, between 665,000 and 1.7 million in the Pacific will migrate because of the submergence of their islands and coasts. A study by Harvard Business Review contends that two-thirds of the world’s largest cities are located dangerous in low-lying coastal areas.
Higher temperature impacts precipitation and, hence, rainfalls. In Africa, several nations experienced below-average rainfall since the late 1990s, a 30% reduction in crop yields, and famines in 2010, 2011, and 2016. Hurricanes, typhoons and other destructive weather events are on the increase.
More heat can lead to deaths due to heat waves. They increase the chances of water- and vector-borne diseases. Smog is more prevalent. Calculations about the direct and indirect costs due to such health impacts range between $350 billion and $900 billion in the US, roughly between 2.5 and 6% of the nation’s GDP.