WHAT's DRIVING CLIMATE CHANGE?
Our planet receives solar radiation in the form of light waves that pass through the atmosphere. Most of this radiation is absorbed by earth, but some of it reflected back in the form of infrared waves. We are currently releasing over 110 tons of greenhouse gases (carbon dioxide, methane, nitrous oxide and hydro-fluoro-carbons) into the atmosphere every 24 hours. As a result, more and more of the outgoing infrared radiation is getting trapped by the Earth's atmosphere, resulting in Global Warming, which then results in a series of climate impacts including melting glaciers and polar ice caps, rising sea levels, and more frequent and intense hurricanes, wildfires and droughts.
EVIDENCE OF CLIMATE CHANGE
For the last 800,000 years, the global atmospheric carbon dioxide level has never exceeded 300 parts per million until 1950. From 1950 to 2020, the level rose from 300 to 410 parts per million, an increase of 37%! This audio clip allows us to experience this dramatic change via sound. The pitch of the tone you hear represents CO2 concentration in the atmosphere, while the pitch and intensity of the plucked strings represent temperature averages. Notice how the the rise in CO2 drives a rise in temperature.
The thickening layer of CO2 in the atmosphere is causing global warming. The planet's average surface temperature has risen by 1.14 degrees Celsius since the early 19th century. Sixteen of the warmest years on record occurred from 2001 onwards and six of the warmest years on record occurred from 2014 onwards. In 2018, the temperature at the North Pole was 28 degrees Celsius hotter than average! This timelapse video from NASA shows how much the planet has warmed in each region since 1880.
Global warming has resulted in drier forests which serve as explosive fuel for wildfires with the slightest of sparks, manmade or otherwise. As temperatures have increased, so has the frequency and intensity of wildfires. In California, 14 of the 20 most destructive wildfires have occurred in the last 15 years. These fires have spread faster and burned more than twice the area of fires in the 1980s and 1990s. This video explains how global warming creates conditions that are ripe for sparking wildfires.
From glaciers to the polar ice caps, Ice covers about 10% of the Earth. With global warming however, this Ice is melting at an alarming rate. Since 1994, we have lost nearly 400 billion tons of glacier ice per year. Around 13% of the minimum area of the Arctic Sea Ice has disappeared each decade, and Antartica has lost about 127 billion metric tons of ice each year. Further, permafrost, which covers over 25% of the Earth's surface is also thawing. NASA's global Ice viewer is a great way to learn more about this issue.
Sea Level Rise
Along with global warming and melting ice sheets, sea levels are rising around the world. In the last century, the global sea level rose by 8 inches, but in the last two decades, the rate of increase is almost double that. The interactive viewer below is a great way to explore the impact of rising sea levels on major population centers like Shanghai, Mumbai, London, Manhattan, Washington DC and Durban. In the Shanghai area for example, 11.5 million people could be impacted by rising seas with 2 degrees of global warming.
Hurricanes & Floods
Since 1995, more than 90% of the excess heat retained by the Earth has been absorbed by the oceans. Warmer ocean temperatures act like fuel for hurricanes, resulting in more frequent, more intense storms with higher wind speeds. Further, warmer oceans and warmer air above the oceans results in more water vapor in the atmosphere, which eventually leads to more severe downpours that cause major flooding. This article provides more data points about the link between global warming and hurricanes.