It’s been a very wet weekend here in Melbourne. Anyone who watched the races at Derby Day on Saturday would have seen that. We’ve had roads flooding, dams filling, and one dog has been made particularly happy by all the water. This blogger recorded 77mm of rain in the 24 hours to 12PM today falling in Melbourne’s eastern suburbs, with plenty more having accumulated in the gauge this afternoon too.

In fact, it’s been quite a wet year as a whole. After a prolonged drought for the best part of the last 14 years, it does in fact seem that the current drought episode has ended. Melbourne’s water storage levels, which have copped a real hiding over this period, have been rising steadily over the course of the past six months, and have for the first time since 2006 have reached 50% of their capacity. Geelong’s water storages are a poofteenth shy of being at 70% capacity, which is a significant improvement from the sub 20% levels they were at just last year.

Unfortunately, I fear that while this rain will be of great benefit to our water supplies, and to the agriculture industry so desperately in need of it, it may be used as a weapon by those against the idea of climate change. Despite the 14 years of evidence, it appears that one good year of rain means that the problem is completely gone, and that we should stop worrying about it. It’s a scarily ignorant attitude.

This rain is not inexplicable by a basic understanding of Australia’s climatic history. We’ve been a land of “droughts and flooding rains” since the days of Dorothea McKellar, but when explaining this it’s best to dispose of the Australian literature for something more Spanish.

I’d think most people would have heard the term El Niño before in relation to weather. In short, an El Niño event is a period where sea surface temperatures in the Pacific Ocean are above average, which results in Australia’s east coast experiencing at times significantly reduced rainfall. The opposite event, known as La Niña, produces the opposite anomaly in sea surface temperatures, and as such brings above-average rainfall to eastern Australia. These events aren’t a new occurrence, in fact in the last 14 years of drought, we’ve had at least 3 significant El Niño events (1997, 2002, 2006) that have all contributed to significantly reduced rainfall here. So it should come as little surprise that, being in the grips of what the Bureau of Meteorology describes as a “Moderate to strong La Niña event in Pacific“, we’ve had a year of above average rainfall.

So you might be tempted to think that it’s all a natural part of life and we’ve nothing to worry about. That would be unwise, as this drought has been one of the most serious and prolonged droughts in recorded history. Sure, a natural climatic process has brought some relief for now, but it doesn’t mean we’re out of the woods forever. To be “out of the woods”, we’d probably need another year or two of this above-average rainfall to bring our water systems back to their pre-drought levels. Then we’d need to return to pre-drought long-term average rainfalls in years where no La Niña event is occurring. If these things all do occur, we can then look at saying that things have returned to “normal”.

I hate to rain on everyone’s parade (boom boom) but those are the facts of the situation. The climate change science also seems to predict that future El Niño events may become more frequent and more severe, and rainfall in normal years will continue to decline. I’m not trying to get everyone down while something good has just happened, I’m just trying to convey the point that we need to be mindful of the bigger picture. One good month of rain does not mean climate change is a hoax, as much as there might be people out there trying to convince you that it does.