Nobody can say with certainty that the devastating tornado that hit Oklahoma on Monday or the strong cyclone that struck Bangladesh last Thursday provide conclusive evidence of climate change.
But scientists have been warning for years that these are the type of extreme weather events we can expect to see happening in different parts of the world as a result of the build-up of carbon dioxide (CO2) in the Earth’s atmosphere.
Although the death toll in Bangladesh was quite low, more than a million people had to be evacuated from their homes as Cyclone Mahasen made landfall. In Oklahoma, the number killed by the tornado and the material damage it caused has yet to be quantified.
There is nothing new about tornadoes in this part of the US, where humid air from the Gulf of Mexico clashes with dry air from the Rocky Mountains. It's the severity of such "twisters", and their frequency, that would appear to bear out warnings from climatologists.
Two significant thresholds have been crossed within the past year.
First, summer sea ice in the Arctic shrank to its lowest level on record last September. Second, the level of CO2 in the atmosphere has now reached 400 parts per million (ppm) – the highest in three million years.
"With 400 ppm . . . we have crossed a historic threshold and entered a new danger zone," UN climate chief Christiana Figueres said on May 13th. "The world must wake up and take note of what this means for human security, human welfare and economic development."
'Storms just happen'
Yet when US senator Sheldon Whitehouse (Democrat, Rhode Island) linked the Oklahoma catastrophe with climate change and castigated Republicans for being in denial, he was branded as a "jackass" and "dipshit" by right-wing bloggers. Storms just happen, they said.
Last Friday, leading American climatologist James Hansen – a hate figure for the denial brigade – accused them of trying to confuse the public by claiming that a slowdown in the increase of average global surface temperatures "proved" that global warming was a hoax.
“In the last decade, [the Earth] has warmed only a tenth of a degree compared to two-tenths of a degree in the preceding decade, but that’s just natural variability. There is no reason to be surprised by that at all,” Prof Hansen said in an interview on BBC Radio 4.
The focus of climate change deniers on such “details” was a “diversionary tactic” to confuse the public “and then we forget about what the main story is” – and that’s the build-up of CO2 in the atmosphere, which would cause “dramatic changes” in the climate.
Tar sands oil
Prof Hansen, who retired last month as director of Nasa's Goddard Institute for Space Studies, was in Europe to lobby the EU to resist pressure from Canada for oil from its Alberta tar sands to be treated the same as other oil – even though its CO2 content is much higher.
And lest anyone imagine that Ireland has escaped, just look at the fodder crisis in the farming sector – as a result of the wettest and coldest March on record. Lorryloads of imported hay and even grass clippings from Dublin Airport are needed to prevent cattle dying.
Yesterday, in a positive move, the European Parliament voted to call on the European Commission to propose a binding renewable energy target for 2030 in advance of an important discussion on energy policy at today’s European Council meeting.
