R. P. Allan1, C. Liu1, N. Loeb2, M. Palmer3, M. Roberts3, D. Smith3, P.-L. Vidale1
1University of Reading/NCAS Climate, 2NASA Langley Research Centre, 3Met Office
Richard Allan is a professor of climate science at the Department of Meteorology, University of Reading, with interests in Earth's energy balance and water cycle
What are the new findings?
Earth is heating up since it is absorbing more sunlight energy than it is losing to space through emitted heat. Energy is currently building up at the rate of 0.6 Watts for each square metre of the globe (equivalent to 150 billion two-kilowatt kettles continuously boiling the oceans). We find that climate simulations are able to capture variations in this heating rate due to natural factors such as volcanoes (which cool the planet) and changes in the ocean relating to El Niño/La Niña (which have both cooling and heating effects). We also find that heating of the planet increased from the 1985-1999 period to the 2000-2012 period, despite slowing in the rate of surface warming. This suggests that the extra energy is warming deeper layers of the ocean.
Why are these findings important?
Understanding how Earth is currently heating up now helps us to gauge how much the planet is going to warm in the future. This is vital for making decisions on how to adapt to and mitigate climate change. The results also show that while surface temperatures have warmed little in the last 15 years, heating of Earth has actually increased, instead warming deeper layer of the ocean. This is consistent with the build up of greenhouse gases in the atmosphere due to human activities, indicating that we can expect global warming to continue into the future.
How did we discover this?
Above: Changes in Earth's yearly average heating rate in observations and simulations 1985-2013. All lines were adjusted to match the observed average heating rate over the 2005-2010 period.
Find out more:
- Read more
- see Richard Allan's webpage
- Take a look at the Journal article
Allan et al. (2014) Geophys. Research Letters, doi: 10.1002/2014GL060962
This research was funded by the UK Natural Environment Research Council DEEP-C project