Climate Change 101
In this blog, we go through the basics of climate change and who is really responsible for it.
What is Climate Change?
Climate change can be defined as long-term shifts in temperature and weather patterns. Over the last 800,000 years, the Earth swinged in and out of ice ages i.e from being completely covered by snow to the kind of world that we live in today. This natural cooling leading to ice ages happens due to periodical changes in Earth’s orbital shape, tilt, and its precession, also known as Milankovitch cycles. On the other hand, the natural warming happens due to the natural greenhouse effect where carbon dioxide and other greenhouse gases are naturally released into atmosphere.
We are currently in one of the Earth’s warming cycles, and this is one of the reasons climate deniers erroneously claim that we are experiencing natural climate change. But what is the evidence that this climate change is anthropogenic i.e caused by humans?
Are humans really causing climate change?
Greenhouse gases, especially carbon dioxide, play a crucial role in driving up the warming on the Earth. Ever since the rise of the Industrial revolution just over two centuries ago, humanity has been burning fossil fuels at an unprecedented rate (see figure 1) and increasing the amount of greenhouse gases in the atmosphere and thereby the rate of warming.
Figure 1: The amount of carbon dioxide emissions from fossil fuel combustion (blue) is exponentially growing since the Industrial revolution and leading to the increase in global carbon dioxide concentrations. (Source: US EIA)
To put things into perspective, the CO2 concentration barely crossed 300-ppm in the last 800,000 years on the Earth through its natural cycles (see figure 2). However, this mark was first breached in 1950 and the trend has been upwards ever since. Today, the CO2 concentration in the Earth’s atmosphere as of June 2022 is 419-ppm. This excessive amount of greenhouse gases in the atmosphere caused by human activities over a short period of time in the Earth’s life is the main cause for today’s climate change. Recently, the Intergovernmental Panel for Climate Change (IPCC) also reported that the human influence on climate change is clear through the rise in greenhouse gas concentrations and observed warming.
The overall rise in average temperature, sea-levels, melting glaciers, and certain extreme weather events are consequences and warning signs of a world going closer to its tipping points courtesy of human activity.
Figure 2: The historical carbon dioxide concentrations in the last 800,000 years on the Earth barely exceeded 300ppm until 1950. (Source: NASA)
