Prof. Veerabhadran Ramanathan：2. Another substance

2. Another substance

What is global warming?

Do you know what the greenhouse effect and global warming are? Imagine driving a car. Half of the CO₂ in the exhaust from the car will remain in the air for about 100 years. The remaining CO₂ will be transported by winds all over the atmosphere, covering the Earth like a blanket. What happens then?
Sunlight is the Earth's primary source of energy. It heats the atmosphere, the surface of the land and the oceans, and generates heat, which we refer to as infrared heat. Certain gases like carbon dioxide in the atmosphere trap this heat. This additional heat trapping warms the planet further. The trapping of infrared heat by the blanket of carbon dioxide and other gases is called the greenhouse effect.

Without the naturally occurring greenhouse gases, the Earth would be too cold for us to live on. The problem is that we don't need a large amount of them. In its natural state, the Earth had a perfect balance of carbon dioxide, water vapor, ozone and cloud. The Earth emits infrared heat into space to prevent too much heat from being trapped. However, humans continue to emit greenhouse gases and air pollutants that are trapping infrared heat that should be escaping, and this is how global warming happens.

Groundbreaking discovery

Let's go back to Professor Ramanathan. After earning his PhD, he joined NASA. While studying the impact of stratospheric ozone depletion on the Earth's climate, he read a paper on the depletion of the ozone layer by CFCs. This sparked his interest in CFCs. He was drawn in part to CFCs because of how the leakage of CFCs from the sealed refrigeration unit had plagued him when he was working for the refrigeration equipment manufacturer eight years earlier.
Since his day job at NASA was seemingly unrelated, he studied and did all his calculations on CFCs at home in the evening. After a month into his research, he realized that CFCs might be having another huge impact on the climate. He spent another three months testing his hypothesis repeatedly. In 1975, he finally discovered that CFCs per unit have a global warming effect 10,000 times greater than that of carbon dioxide.

This groundbreaking discovery helped his career and family life greatly. It brought an unknown scientist from India into the mainstream of climate and atmospheric science study, and opened the door for an immigrant researcher to conduct his own research. It also helped his married life. His wife may have been frustrated by him spending all of his days and nights just working on his research; however, he showed her that he had the potential to become a great researcher. At the same time, this discovery unveiled the problem of non-CO₂ greenhouse gases to the world.

1978, Age 34

A few years later, he and other researchers around the world discovered other trace gases. The study of trace gases contributed to the creation of a new field of study called climate-chemistry interactions. Recognizing the importance of his CFC discovery, NASA and the United Nations invited an international group of scientists in 1983 to review the science behind non-CO₂ greenhouse gases, Professor Ramanathan was asked to chair the committee. Under his leadership, the group released a report which concluded that as of the 1980s, greenhouse gases other than carbon dioxide were contributing nearly as much as carbon dioxide was to global warming.

3. Short-lived climate pollutants (SLCPs)