illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Climate scientists never talk about water vapor, which is the strongest greenhouse gas, because it undermines their CO2 theory.
Answer:
There is no climate model or climate textbook that does not discuss the role water vapor plays in the Greenhouse Effect. It is the strongest Greenhouse gas, contributing 36% - 66% to the overall effect for vapor alone, 66% to 85% when you include clouds. It is however, not considered as a climate "forcing…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
The current warming is just part of a natural cycle.
Answer:
While it is undoubtably true that there are some cycles and natural variations in global climate, anyone who wishes to insist that the current warming is purely natural or even just mostly natural has two challenges. Firstly, they need to identify just what the mechanism is behind this alleged natural cycle, because absent a forcing of some sort, there will be no change in…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
It was just as warm in the Medieval Warm Period (MWP) as today, in fact Greenland was green and they were growing grapes in England.
Answer:
There is actually no good evidence that the MWP was indeed a globally warm period comparable to today. Regionally, there may have been places that did exhibit notable warmth, Europe for example, but all of the various global proxy reconstructions agree that it is warmer now and the temperature is…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
It was even warmer than today during the Holocene Climatic Optimum without any human influence.
Answer:
Actually, it turns out that though there may have indeed been some temperatures in the same range as today, this was regional to the northern hemisphere and confined to the summer months! What's more, the cause is understood (orbital forcing similar to what controlled the Ice Ages), just as today's cause is understood (CO2 emissions),…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
The CO2 concentration lags behind temperature by centuries in the glacial-interglacial cycles, so clearly CO2 does not cause temperatures to rise, temperatures cause CO2 to rise.
Answer:
A close examination of the CH4, CO2 and temperature fluctuations recorded in the Antarctic ice core records does in fact reveal that yes, the temperature moved first in what is, when viewed coarsely, a very tight correlation. But what it is not correct,…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Global warming is happening on Mars and Pluto as well. Since there are no SUV's on Mars, CO2 can't be causing Global Warming.
Answer:
Warming on another planet would be an interesting coincidence, but even if it were the case it does not necessarily have to have the same cause. The only relevant factor the Earth and Mars share is the sun, so if the warming were real and related it would logically be due to the sun. Well the sun is being…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Correlation is not proof of causation. There is simply no proof that CO2 is the cause of the current warming.
Answer:
There is no "proof" in science, that is a property of mathematics. In science, one must look at the balance of evidence and formulate theories that can explain this evidence. Where possible scientists make predictions and design experiments to confirm, modify or contradict their theories and must modify these theories as…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Global Warming is just a hoax perpetrated by environmental extremists and liberals who want an excuse for more big government.
Answer:
Here is a list of "enviro-Nazis" and "left-wing loonies" who believe that Anthropogenic Global Warming is real and well supported by sound science:
NASA's Goddard Institute of Space Studies (GISS) - http://www.giss.nasa.gov/edu/gwdebate/
National Oceanic and Atmospheric Administration (NOAA) - http://www.…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Climate is complicated and there are lots of competing theories and unsolved mysteries. Until this is all worked out one can't claim there is consensus on Global Warming Theory and until there is we should not take any actions.
Answer:
Sure there are plenty of unsolved problems and active debates in climate science. But if you look at the research papers coming out these days, the debates are about things like why model predictions of…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
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.
Answer:
Urban Heat Island Effect has been examined quite thoroughly and simply found to have a negligible effect on temperature trends. Real Climate has a detailed discussion of this here. What's more, NASA GISS takes explicit steps in their analysis to remove any such spurious…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
The surface temperature record is so 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.
Answer:
There is actually some truth to the part about the difficulties, there are many of them that…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
It was way colder than normal today in Wagga Wagga, this is proof that there is no Global Warming.
Answer:
Does this even deserve an answer? If we must...
The chaotic nature of weather means that no conclusion about climate can ever be drawn from a single data point, hot or cold. The temperature of one place at one time is just weather, and says nothing about climate, much less climate change, much less again global climate change.
This…
illconsidered | February 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
The Antarctic Ice sheets are actually growing, which would not be happening if Global Warming were real.
Answer:
There are two distinct problems with this argument. First, any argument that tries to use a regional phenomenon to disprove a global trend is simply dead in the water. Anthropogenic global warming theory does not predict uniform warming throughout the globe. We need to assess the balance of the evidence. In the case of this…
illconsidered | January 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
H2O is 95% of the Greenhouse effect, CO2 is insignificant.
Answer:
According to all of the scientific literature and climate experts I am aware of regarding this question, CO2 contributes anywhere from 9 to 30% towards the overall greenhouse effect. Depending on the method you use to determine these percentages they may even add up to more then 100% due to overlap and saturation of the particular frequencies of infra-red radiation each…
illconsidered | January 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Climate has always changed, why are we worried now and why does it have to be humans fault?
Answer:
Yes, climate has varied in the past and it has varied for many different reasons, some better understood than others. The present day climate change is very well understood and is different. Simply noting that something happened before without humans does not in any logical way show that humans are not causing it today.
For example, we see…
illconsidered | January 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
Global surface temperatures recorded over just one hundred and some years is not long enough to draw any conclusions 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…
illconsidered | January 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
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: every year since 1992 has been warmer than 1992 the ten hottest years on record occurred in the last 15 every…
illconsidered | January 25, 2006This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
A few glaciers receding today is not proof of Global Warming, glaciers have grown and receded differently in many times and places.
Answer:
Firstly, it is more than "a few glaciers" that are receding, it is a pervasive, sustained and accelerating global trend. The National Snow and Ice Data Centre (NSIDC) maintains a chart of global glacier mass balance, and for as far back as their data allows us to look, all but a few years have…