Hot, hot, hot. April was the seventh month in a row to smash global temperature records, but a brief respite could be on the horizon.
Since October, every month has exceeded the 1951-1980 monthly .
The ongoing heat wave is being fuelled by a double whammy 鈥� background global warming and a strong El Ni帽o cycle.
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The relative contributions of these two phenomena are difficult to gauge, but clues can be found in previous El Ni帽o cycles, says of the Australian Bureau of Meteorology.
鈥淚f you compare the temperatures of the last 12 months with the same stages of the last strong El Ni帽o event in 1997 and 1998, it鈥檚 about 0.3 掳C warmer this time round,鈥� he says. 鈥淭his is consistent with an overall warming trend.鈥�
However, the record run may be interrupted when La Ni帽a, the opposite weather cycle to El Ni帽o, kicks in towards the end of the year, he says.
[youtube]https://www.youtube.com/watch?v=-J3PFKXSY_Y[/youtube]
El Ni帽o is a cyclical weather pattern that warms the central and eastern tropical Pacific Ocean, while La Ni帽a has the opposite cooling effect.
The US government鈥檚 National Oceanic and Atmospheric Administration (NOAA) that the current El Ni帽o phase, which began in 2015, has a 75 per cent chance of switching to La Ni帽a as early as September.
This transition is likely to reduce sea surface temperatures in the central tropical Pacific to between -0.5 掳C and 0.5 掳C from average, from a high of more than 2 掳C above average when El Ni帽o peaked in November, according to the .
Average global temperatures are likely to fall slightly as a result, Trewin says. 鈥淎 strong La Ni帽a like we saw in 2010 and 2011 will drop global temperatures by 0.1 to 0.2 of a degree, but weaker events won鈥檛 have as strong an impact,鈥� he says.
Even if La Ni帽a does put the brakes on global temperature, the effect is likely to be short-lived, says of the University of New South Wales, Australia.
鈥淟a Ni帽a sometimes lasts for a year, sometimes two years,鈥� he says. 鈥淚t will be very interesting to see what happens when La Ni帽a emerges. If records are still being broken, it will suggest that it is background warming that is playing the key role.鈥�
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