Global warming is accelerating, extreme heat is already endangering lives in India, and Australia’s Safeguard Mechanism is failing to deliver meaningful emissions cuts from the country’s biggest industrial polluters.

Global warming has accelerated in last decade

The rate of increase in the global temperature has been pretty steady since the 1970s (about 0.2oC per decade). But there has been recent debate among climate scientists (sometimes with a whiff of acrimony) about whether the rate has taken a tick upwards in the last decade and what may have caused any change. The acceleration camp (most notably James Hansen) say, “it’s obvious, just look at the graph of global average temperatures, particularly the record annual highs”. The doubters want to see proof that any recent rate change is statistically significant and suggest that variations in natural rather than anthropogenic causes may be responsible for any change that does exist.

A recent study sought to tackle these issues head-on. First, the investigators removed the estimated influence of variations in the three main natural factors: the El Nino/Southern Oscillation (ENSO), volcanic activity and solar activity. Then they the compared annual average global temperatures statistically over the period 1970-2025.

To summarise the findings:

Around 2015 the rate of warming per decade increased from about 0.2oC to 0.35oC (with over 98 per cent confidence in the finding).

The rate of warming over the last decade is far higher than any decade since 1895.

Global warming will exceed 1.5oC before 2030.

It is likely but not yet proven that the cause of the acceleration is the reduction of aerosols (small particles of pollution from the burning of fossil fuels) in the atmosphere as a result of stricter air pollution controls. The particles reflect incoming solar energy and have had until recent years a general cooling effect on the Earth of about 0.4o

The authors conclude that this not unexpected accelerated warming “is a cause of concern and shows how insufficient the efforts to slow and eventually stop global warming under the Paris Climate Accord have so far been. Stopping this (accelerating) trend is in our hands: studies show that global warming will stop around the time humanity reaches zero CO2 emissions. In the current political climate,........

© Pearls and Irritations