For many years I was on the comfortable side of the global warming debate. After changing position, I often contemplated why there is so much polarization between the two sides. Considering my own shifted position, I could find a reason: both sides have a different definition about what they mean by global warming or climate change.
As said some posts ago, definitions are very important. It can make the difference of having less, equal and more woodland, depending what definition people have for it and their counting method.
But it is as bad with the terms that forms the heart of the global warming/climate change debate. Let’s first have a look at: Global Warming
At first glance it all seems pretty clear, the temperature of the earth is rising globally. Sure, but temperatures are not rising everywhere on earth. Some places will warm, other will cool, other will stay the same. So global should be defined more clearly. Is it an area? In this case, how much area is enough to speak about global warming?
Or is it an average of the temperatures around the world? In this case, what defines global warming: land, ocean, land + ocean or atmosphere? Which dataset to use: Giss, HadCrut, BEST, UAH, RSS,…? What if one or more are not in agreement?
If this is settled, then what is considered a temperature increase that is deemed catastrophic: 0.5, 0.8, 1, 2, 4 °C or more per century or per doubling of CO2 concentration? Or just everything above 0? On what time frame? And compared against what? A cool period? A warm period? A static period? The last 30 year? 1 complete cycle?
There is a lot of stretch in the terminology. People talking to each other about global warming can be talking about two completely different things. If they don’t realize this, misunderstandings can occur. Even more, an ill defined term can be stretched as one goes along. For example: if temperatures go up, one can talk about global warming. If temperatures of one or more series are not going up, maybe one dataset still goes up and can still confirm global warming. If all series stays the same or go down, one could still define warming as having a higher temperature than previous years/decades, just focusing on the rising part of the cycle.
Then we didn’t even talk about predicted/projected consequences of global warming. Some say hurricanes are increasing in a warming world, other say there is not much confidence. The same with droughts. Some attribute it to global warming, some don’t.
An example of a stretch in a vague definition is the shift from temperatures that were highest in the last x years to warming since 1950. Which excludes the current pause, but also the inconvenient 1930s-1940s. This means it is still possible to talk about a warming. Okay, not now but in the past. But is that what the public understands when they hear this? They would think it is currently still warming, so alarming.
Another example is the focus shifting to single events on a limited area like the drought/forest fires in part of the contiguous United States (just a tiny area on the globe) or a storm like Sandy (ignoring the all time low storm count/intensity).
With no clear definition everything, great or small, can be taken as evidence of global warming.
The same with the term: Climate Change
Also here at first glance it seems pretty clear. There is at least one changing element in climate.
But on the other hand, climate is the average over a longer timespan. Which timespan does one take? 1, 5, 10, 15, 30, 60 years or even longer? Which elements: temperature, precipitation, snowfall, sea level, storms, ice area,… do you think are important? And what if one takes change of weather and take this as proof of climate change? Then one can proof everything.
Change is the norm. If one takes variability in a chaotic system as proof of change, there is no limit on the proof one can accumulate!
In conclusion: with those ill defined terms all holes are completely covered for those who want to sound the alarm. If temperatures are not cooperating, surely there will be some change somewhere, anywhere. Call it moving goalposts, non falsifiability or whatever. But this also means that even in evidence of the contrary, a view can be persistently kept alive.
That is not all. Imagine the confusion when people talk about global warming and actually mean catastrophic anthropogenic global warming. When scientists in the media state that it was warming from the 1950s (which is correct) then the public thinks that it proves “we caused it” and that it is “catastrophic”. Been there, done that. Adding to the “overwhelming” evidence that (catastrophic) global warming is happening and should be prevented.
How could alarmists and skeptics ever talk together constructively when they have no common definitions of “global warming” and “climate change”? There is more agreement between them then is admitted, but their different definitions lets them talk beside each other.
More, if there is no clear definition of what is “global warming” or “climate change”, how can we know when this global warming or this climate change becomes/became/is catastrophic?
When using such vague definitions, one can explain about anything.
Trust, yet verify 