More slow motion tennis (i.e. serve in Monday’s paper, return arrives three days later, response a week after that… I have a nostalgic affection for the printed newspaper as a medium, but sheesh!) on climate change in The Canberra Times.

This letter appeared on 11 June:

Australian National University scientist Will Steffen (“Fielding draws fire for doubting global warming”, June 9, p4) responds to Senator Steve Fielding’s doubts about the connection between carbon dioxide and climate change by stating that warming in the last half century is “incontrovertible”.

He neglects to state also that there has been cooling since 1998, despite increasing carbon dioxide emissions.

It’s not surprising that Fielding and others remain unconvinced.

Fielding needs to be reminded that continuing carbon dioxide emissions are lowering the pH of seawater, and threatening the myriads of marine organisms with a calcium carbonate skeleton, including reef corals. This major threat to the marine environment is a matter of straightforward chemistry which Fielding, an engineer, should understand.

Its reality has been demonstrated by experiments and field studies on marine organisms, and it remains a threat regardless of climate change.

Max Brown, Mawson

I sent this response, published on June 17:

Max Brown (Letters, 11 June) points out the real dangers in ocean acidification because of CO2 buildup, but then unfortunately recycles the well-worn myth that the world has been cooling since 1998 – an unusually hot year due to a strong El Niño effect.

Those who seek to spread doubt about global warming typically pick 1998 as their starting point, and with some careful selection of sources and a little torturing of the data can produce a graph that looks like cooling.  But if you start at, say, 1997 or 1999 instead, the house of cards falls down – it shows strong warming.

Climate is all about long term trends, not short term effects such as last year’s La Niña.

Short answer: the long term trend since 1998 is still definitely one of warming.  See for more details.