This year I launched the Skeptical Science app for iPhones, Nokias and the fast-growing Android phones. The app looks at many arguments from climate sceptic and identifies a common pattern – that sceptics focus on small pieces of the puzzle while neglecting the full body of evidence.
Our app aims to gives you the full picture, with all the evidence, scientific context and links to peer-reviewed research. It has another useful function – users can send me reports on which sceptical arguments they encounter.
Yet last week, the respected US National Oceanic and Atmospheric Administration (NOAA) published 10 measurable planet-wide features used to gauge global temperature changes. Sea level-rise, ice-melt, ocean heat and many other indicators are all moving in the direction of a warming planet. Climate sceptics' narrow focus on a single data set is a classic example of missing the forest for the trees.
When the iPhone app first came out, some sceptics wistfully wished for their own iPhone app. I was curious to see such a thing myself. The cherrypicking nature of climate scepticism leads to an interesting phenomenon – sceptic arguments frequently contradict each other. One week, we're told El Nino is the cause. Next week, it's cosmic rays. No wait, we're cooling... Hold on, it's warming again, but this time, it's because of CFCs. Could anyone compile the many sceptic arguments into a single app without a mess of contradictions?
Now we can find out. An iPhone app, Our Climate has just been released with contributors including notable sceptics such as Richard Lindzen, Roy Spencer and even the UK's own Lord Christopher Monckton. The first thing you see when you open the app is a Top 10 list, featuring the "Top 10 climate tips you should know'. Their Number 1 tip argues that climate has suffered rapid swings in temperature in the past. You'll often find sceptics citing this fact as if it's never occurred to climate scientists.
In reality, there have been many peer-reviewed studies into past climate change, and what they find is when our planet warms, positive feedbacks amplify the warming (such feedbacks are where higher temperatures bring higher emissions and faster warming – an example would be a reduction in sea ice leading to increased heating because the darker sea absorbs more heat than lighter ice). What this means for us today is the warming from our CO2 emissions will be amplified by positive feedbacks.
Their Number 2 tip argues that negative feedback (a warmer world leading to less water vapour and therefore trapping less heat, for example) should dampen the warming from CO2. So we have the Number 1 sceptic tip presenting evidence for positive feedback and the second-place sceptic argument presenting evidence for negative feedback. Amazingly, both sets of evidence lead to the same conclusion that humans can't have much of an impact on climate. Confused? Whether desired or not, that's the effect.
Throughout the Our Climate app, you'll find many examples of what looks like cherrypicking. We're told CO2 is plant food, but nowhere is it mentioned that plants also need water. Global warming has already caused an increase in drought severity over the last century, which is only going to get worse. We're told CO2 has been higher in the past, but it's not mentioned that solar output was also lower in the past, balancing out the warming effect from higher CO2. The app describes itself as "comprehensive" but perhaps that should be amended to "comprehensively misleading".
Climate change is a serious issue. For us to properly understand what's happening to our planet, we need to consider all the evidence. When you try to explain climate change using cherrypicked arguments, you end up with a misleading picture that lacks internal consistency. This is in strong contrast to reports like last week's State of the Climate 2009 by the NOAA, which found multiple sets of direct measurements all pointing to a single, coherent picture.
• John Cook runs the Skeptical Science site
guardian.co.uk © Guardian News and Media Limited 2010