By Evan Gowen
The picture above is a screen capture of the current conditions in
Winnipeg, Manitoba, Canada, a city near where I grew up. It is currently
21°C, which is pretty close to what we are expecting in Canberra today. The only difference is that Winnipeg is still technically in winter, and the normal high is 0°C (and the previous record high was 8.8°C)! Temperatures are expected to be upwards of 25 degrees warmer than normal. To put it in perspective, a normal high in Canberra for March is 24.5°C, and the record high in March is 37.5°C (see here). If Canberra were to be 25 degrees above normal, it would have to be nearly 50°C, which would be well above the all time record high!
Last week, the Climate Commission released a short report (see here), authored by Matthew England, David Karoly, and ANU’s Will Steffen giving an overview of global climatic conditions and the impacts on Australia. They warn people not to confuse independent weather events with the overall trend of global warming. The large floods and cool weather that we experienced in Australia does not disprove global warming any more than the heatwave in Winnipeg proves that it is happening.
Some surprising observations of the La Nina event that governed
Australia’s weather during the past two years. Even though La Nina
generally leads to colder than normal conditions, and the present La
Nina was one of the most intense on record, global temperatures remained
well above what they were throughout the 20th century. That seem
confusing to those living in Australia who are now lamenting at the
summer that never truly took hold. This is why caution should be taken
when trying to interpret global trends from a single source. For
example, I went back to Canada last July, temperatures commonly reached
the mid to high 30s, which is more what you would expect here in
Australia in the summer. Even so, considering the heatwave in central
Canada, and the cool trend in Australia, the average global temperature
last year was 0.4 degrees above the 1961-1990 average temperature.
Another observation is that even though most of Australia experienced
above average rainfall, the extreme southwest part of Australia
experienced the driest year on record.
With La Nina conditions ending soon (see here), Australia is likely to return to
dry conditions. The conclusion of the the Climate Commission report is
that Australia should expect conditions similar to the droughts that
happened in the first decade of the 21st century, punctuated with
extreme rainfall events in La Nina years. So even though the cool wet
weather we experienced during the past two years seems unusual, it is
actually in line with what is anticipated with a warming earth. Climate
is a statistic, and should never be confused with short term weather