How to Talk to a Climate Skeptic: Responses to the most common skeptical arguments on global warming

‘The satellites show cooling’–No, they don’t

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: Satellite readings, which are much more accurate, show that the earth is in fact cooling.

I wonder how long before this one stops coming up?

‘It’s cold today in Wagga Wagga’–Weather and climate are different

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: It was way colder than normal today in Wagga Wagga, proof that there is no global warming.

Does this even deserve an answer? If we must ...

‘The temperature record is unreliable’–But temperature trends are clear and widely corroborated

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: The surface temperature record is full of assumptions, corrections, differing equipment and station settings, changing technology, varying altitudes, and more. It is not possible to claim we know what the "global average temperature" is, much less determine any trend. The IPCC graphs only say what the scientists want them to say.

‘Glaciers have always grown and receded’–A few glaciers melting does not mean global warming

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: A few glaciers receding today is not proof of global warming. Glaciers have grown and receded differently in many times and places.

‘One record year is not global warming’–Luckily, there are plenty more years to consider

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: So 2005 was a record year. Records are set all the time. One really warm year is not global warming.

Answer: This is actually not an unreasonable point -- single years taken by themselves can not establish or refute a trend. So 2005 being the hottest globally averaged temperature on record is not convincing. Then how about:

‘The scientists aren’t even sure’ — No scientist ever is

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: Even the scientists don't know that the climate is changing more than normal and if it's our fault or not. If you read what they write it is full of "probably," "likely," "evidence of" and all kinds of qualifiers. If they don't know for sure, why should we worry yet?

‘One hundred years is not enough’–Yes it is

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: One hundred and some years of global surface temperatures is not long enough to draw any conclusions from or worry about anyway.

Answer: The reliable instrumental record only goes back 150 years in the CRU analysis, 125 in the NASA analysis. This is a simple fact that we are stuck with. 2005 was the warmest year recorded in that period according to NASA, a very close second according to CRU. Because of this limit, it is not enough to say today that these are the warmest years since 150 years ago, rather one should say 'at least':

1998 and 2005 are the warmest two years in at least the last 150.

‘Warming is due to the Urban Heat Island effect’ — No, it isn’t

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: The apparent rise of global average temperatures is actually an illusion due to the urbanization of land around weather stations, the Urban Heat Island effect.

‘Mauna Loa is a volcano’ — CO2 rise is measured on top of a volcano!

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: CO2 levels are recorded on top of Mauna Loa ... a volcano! No wonder the levels are so high.

(image courtesty of Global Warming Art)