Why CO2 is the primary driver of climate change

Sub : Env

SEC: Climate change

Context:

India’s CO2 emissions from burning fossil fuels are projected to increase by 6% in 2024, the highest growth among major economies.
This projection comes from the Global Carbon Project, an organization that quantifies global greenhouse gas (GHG) emissions.
It also predicts that global fossil-based CO2 emissions are set to reach a record high of 37.4 billion tonnes in 2024, a 0.8% increase from 2023.

Greenhouse Effect:

The Sun emits shortwave radiation absorbed by the Earth’s surface, which is then re-emitted as longwave infrared radiation.
Greenhouse gases (GHGs) such as CO2 and methane trap this infrared radiation, preventing heat from escaping into space.
GHGs have three or more atoms, which gives them a larger variety of ways to stretch and bend and twist, allowing them to absorb and trap a wider range of infrared wavelengths.
These gases maintain Earth’s temperature, enabling life. However, excessive GHG concentrations cause global warming.

Global warming:

Since the industrial revolution, there has been a constant rise in the amount of some of the GHGs, especially CO2, due to human activities like burning fossil fuels.
As a result, more heat is getting trapped in the atmosphere, leading to a rise in global temperatures.

Why CO2 drives Global Warming:

Abundance: CO2 is responsible for 70% of global warming, as it is more prevalent than other GHGs. Since the Industrial Revolution, human activities have increased atmospheric CO2 by 50%.
Longevity: CO2 persists in the atmosphere far longer than other GHGs: 40% remains for 100 years, 20% for 1,000 years, and 10% for 10,000 years. In contrast, methane (CH4) lasts a decade and nitrous oxide (N2O) about a century.
According to the Intergovernmental Panel on Climate Change (IPCC) CO2 has the greatest warming effect or Radiative Forcing (RF) among GHGs.

Water vapour:

Water vapour is the most abundant GHG in the atmosphere. However, water vapor has a short atmospheric cycle, averaging about 10 days, and does not accumulate in the atmosphere like CO2. As a result, its heating effect is significantly less than that of CO2.