A slow-down in global warming is not a sign that climate change is ending, but a natural blip in an otherwise long-term
upwards1 trend, research shows. In a
detailed2 study of more than 200 years' worth of temperature data, results backed previous findings that short-term pauses in climate change are simply the result of natural variation.
The findings support the likelihood that a current hiatus in the world's year-on-year temperature increases - which have stalled since 1998 - is temporary.
Scientists from the University of Edinburgh analysed real-world historic climate records from 1782 to 2000, comparing them with computerised climate models for the same timescale.
They were able to separate the influence on climate trends of man-made warming - such as from greenhouse gas
emissions3 - and of natural influences in temperature - such as periods of intense sunlight or
volcanic4 activity.
This showed that
random5 variations can cause short term interruptions to climate patterns in the form of a pause or surge in warming, in both the real data and in the models, typically
lasting6 up to a decade. Extreme natural forces, such as strong volcanic
eruptions8, were shown to disrupt climate trends for decades.
The research highlights the impact of volcanic eruptions on climate, when particles produced can reflect sunlight from Earth, causing long-lasting cooling. The
eruption7 of Mount Tambora in Indonesia in 1815 was among the biggest in recent times, causing a so-called year without summer. Scientists estimate that, if it occurred today, it would cause a 20-year climate hiatus.