Understanding temperature anomalies

Source: The post is based on the article “Understanding temperature anomalies” published in The Hindu on 26th April 2023

What is the News?

March 2023 has been declared as the Earth’s second-warmest March since global record-keeping began in 1850.

Why was March 2023 the second warmest?

March 2023 was indeed the second warmest in the instrumental record.

The warmest March occurred just a few years ago in 2016, when the biggest El Niño of the 21st century triggered a ‘mini’ global warming.

Why was March 2023 the second warmest and not the warmest?

Each year’s March can be warmer or cooler than the March of the year before. Natural climate variability, including events like El Niño, can temporarily spike temperatures.

This global distribution of temperature anomalies is due to land-ocean-atmosphere processes that dynamically determine the weather and climate. 

Global warming does not mean each month or each year will be warmer than the previous month or the previous year. 

Instead, a better place to begin would be by averaging the weather over a decade. Decade to decade warming clearly shows that humans are now ensuring each decade is warmer than the one before.

What is Temperature Anomaly?

A temperature anomaly is a departure, positive or negative, of a temperature from a base temperature that is normally chosen as an average of temperatures over a certain reference period often called a base period. 

Commonly, the average temperature is calculated over a period of at least 30 years over a homogeneous geographic region, or globally over the entire planet.

For example, an anomaly of +2.0 degrees means the average temperature was 2 degrees higher than the long-term average.