Is Global Warming Accelerating?

Is Global Warming Accelerating?

Sub: Geo

Sec: Climatology

Why in News

• The European climate service Copernicus has reported that January 2025 was the hottest January on record, surpassing the previous record set in January 2024. Despite factors such as a cooling La Niña and predictions of a slightly less hot 2025, global temperatures continue to rise.

Rising Global Temperatures:

• January 2025 was 09°C warmer than January 2024.
• The global temperature was 75°C higher than pre-industrial levels.
• 18 of the last 19 months have seen temperatures exceed 5°C above pre-industrial times.
• Scientists, however, state that the 5°C threshold will not be officially breached until the global average remains above it for 20 years.
• The primary driver of record heat is the accumulation of greenhouse gases (GHGs) from the burning of fossil fuels such as coal, oil, and natural gas.
• Natural Climate Variability:
  • The El Niño–La Niña cycle significantly influences global temperatures.
  • El Niño, a warming phase in the equatorial Pacific Ocean, contributes to temperature spikes.
  • La Niña, the cooling phase, typically dampens global warming effects.
  • Despite a La Niña event starting in January 2025, temperatures remain high, contradicting expectations.

Refer: 2024: The Year Humanity Breached the 1.5°C Global Warming Limit

What is La Niña?

• La Niña is a phase of the El Niño Southern Oscillation (ENSO), a climate phenomenon that involves variations in sea surface temperatures and atmospheric pressure in the tropical Pacific Ocean.
• It can influence weather patterns globally, affecting rainfall, temperatures, and storm systems.
• The ENSO has three phases, which occur in irregular cycles of two to seven years.:
  • El Niño (warm phase),
  • La Niña (cool phase),
  • Neutral phase.

What happens during La Nina:

• In La Niña, the trade winds (winds blowing from east to west across the Pacific) are stronger than usual, pushing warm surface waters to the western Pacific.
• This allows cooler waters from below the surface to upwell along the eastern Pacific, leading to lower-than-normal sea surface temperatures in this region.
• In India, El Niño is associated with decreased rainfall and higher temperatures, while La Niña is associated with increased rainfall and hence lower temperatures.

About El Niño:

• In the El Niño phase, the trade winds weaken, leading to lesser displacement of warmer waters off the South American coast.
• Consequently, the eastern Pacific becomes warmer than usual.

Neutral phase:

• In the neutral phase, the eastern side of the Pacific Ocean (near the northwestern coast of South America) is cooler than the western side (near the Philippines and Indonesia).
• This is due to the prevailing wind systems that move from east to west, sweeping the warmer surface waters towards the Indonesian coast.
• The relatively cooler waters from below come up to replace the displaced water.