Source: This post on Breaching 1.5°C has been created based on article “What breaching 1.5°C means ” published in Indian Express on 11th January 2025.
UPSC Syllabus- GS Paper 3 – Environment
Context: The article discusses the significant milestone in climate change: the year 2024 became the first calendar year to breach the 1.5°C global warming threshold, marking a critical point in the planet’s warming trend. This breach, measured relative to pre-industrial temperatures (1850-1900 averages), is based on data from multiple global datasets, including the Copernicus Climate Change Service and the World Meteorological Organization (WMO).
What does breaching 1.5°C mean, and why is it significant?
- Significance of 1.5°C: The 1.5°C mark, referenced in the 2015 Paris Agreement, is an arbitrary threshold indicating severe climate impacts as temperatures rise. It doesn’t signify an abrupt change but emphasizes worsening climate effects.
- 2024 Breach: The year 2024 became the first calendar year to breach the 1.5°C warming threshold, with a global annual average temperature of 1.6°C above pre-industrial levels (1850-1900).
- Paris Agreement Context: The 1.5°C target refers to long-term trends over decades, not individual years. Therefore, this breach does not imply the Paris Agreement has been violated yet.
What data confirms the breach?
- Copernicus Climate Change Service: Recorded a 1.6°C rise above pre-industrial levels for 2024.
- World Meteorological Organization (WMO): Using six datasets, WMO reported a warming of 1.55°C for 2024.
- Historical Context: 2024 surpassed 2023 as the warmest year on record. For comparison, 2016, influenced by a strong El Niño, was 1.29°C warmer than pre-industrial levels.
Why did 2024 become the warmest year ever?
- Contributing Factors:
- Mild El Niño conditions during 2023-2024.
- Other El Niño-like systems in different ocean regions.
- The 2022 Tonga volcanic eruption, which altered atmospheric composition.
- Reduced sulphur dioxide emissions from the shipping industry, which otherwise reflect solar radiation.
- The Sun’s solar maximum phase during 2024, increasing solar energy reaching Earth.
- No Single Cause: ECMWF notes that warming resulted from a combination of factors, and further analysis is required.
How do 2023 and 2024 compare to previous years?
Exceptionally Warm Years:
- 2023: 1.45°C above pre-industrial levels.
- 2024: 1.6°C above pre-industrial levels, breaking the previous record.
- Monthly Trends: Every month since July 2023, except July 2024, was over 1.5°C warmer than pre-industrial averages.
Does this breach mean the 1.5°C target is unachievable?
- Not Yet: A single-year breach does not mean the Paris Agreement target is unattainable. The focus is on multi-decade trends.
- Future Outlook: With global warming rates exceeding 0.2°C per decade, breaching the 1.5°C target within the 2030s is highly likely.
What are the long-term implications of the 2024 breach?
- Global Emissions: Emissions are still rising, and 2030 emission cut targets are unlikely to be met. This increases the probability of 1.5°C breaches becoming the norm.
- Projections: According to the WMO, annual temperatures could reach 1.9°C above pre-industrial levels before 2028. There’s a 50% chance of the five-year average exceeding the 1.5°C mark by 2028.
What does 2025 and beyond look like?
- 2025 Forecast:
- Not expected to surpass 2024 as the warmest year.
- Likely to remain in the 1.1°C to 1.4°C range above pre-industrial levels, consistent with the past decade.
- Long-term Trends: The UK Met Office predicts 2025 might be the third warmest year ever, after 2024 and 2023.
