Is it best to talk of global warming or climate change? Are they the same thing?
Well no, not exactly.
The simplest explanation is that global warming is climate change in one direction – specifically where energy in the earth's atmosphere and ocean system increases and it gets hotter.
But climate can also cool. There have been periods in the geological past when the earth’s surface has been much cooler than the present. So much cooler that we recognize ice ages, lots of them - some were short, others long and intense.
Climate change means any change, whilst global warming is a specific type of change.
This is the explanation of the physical phenomenon, the objective one used by the scientists.
Most people seem to relate more to the term global warming. Currently there are over 3x more Google searches for global warming than there are for climate change.
And it used to be that everyone - activists, media people and politicians together - talked mostly of global warming. The earth is getting hotter thanks to an increase in the atmosphere of greenhouse gases that result in the warming effect.
The brief explanation of this is that the wavelength of energy arriving on the earth’s surface through the atmosphere is shorter than that reflected back towards space - a simple law of physics. Some gases in the atmosphere let the shorter waves through but block the longer wavelengths, so the energy is bounced back down to earth, trapped, effectively heating things up.
In the absence of the greenhouse effect mother earth would be frigid and the planet’s surface too cold for water to be liquid. The logic of this important warming phenomenon is that global warming or climate change happens primarily because the concentrations of greenhouse gases in the atmosphere increase.
So global warming climate change is the warming part of the cycle and it is caused by increase in greenhouse gas concentrations in the atmosphere.
And this is where the confusion comes because we have attributed the current warming trend to a specific cause – us.
ironically this landfill fire releases less greenhouse gas than if the refuse decayed within the landfill as then it would release methane that is a more potent greenhouse gas than CO2 — city landfill site, Gaborone , Botswana
Policy statements have confounded the confusion.
The United Nations Intergovernmental Panel on Climate Change (IPCC) defines climate change as coming from any cause, human or natural. This carries the implication that the world might cool as readily as it might warm up - an understandable assumption given the scientific evidence from the distant past.
The United Nations Framework Convention on Climate Change (UNFCCC) defines climate change as attributed solely to human causes. The implication is that the world will warm and this warming is because of human actions.
Environmental policy around global warming or climate change gets more detailed discussion in climate change politics.
So what happened to the rhetoric of the politicians on global warming or climate change?
About the time of the first George W Bush administration, politicians, commentators and, increasingly the media, dropped the term global warming in favor of climate change.
Why? Well that depends on how cynical you want to be. And how cynical depends on whether you think that the global climate change we are experiencing is due to human action - anthropogenic climate change – or is just part of the normal scheme of events on a dynamic earth – natural climate change.
If you’re a left brainer you will probably figure climate change to mean any change from any cause - the objectivity flavored view from the IPCC.
So if you feel mostly objective, then climate simply changes to get hotter or colder, wetter or drier, according to a dynamic than has underlying causes.
And there are many of these causes of climate change.
If you’re more of a right brainer with an affinity for the complexity of climate change as an idea, you might take global warming or climate change to mean a warming due to human actions increasing concentrations of greenhouse gases - the politically flavored UNFCCC perspective.
The important thing is to realize that climate can get warmer and it can get colder.
At a given location on the earth it It can get wetter or drier; more stormy or calmer; more predictable or erratic. And all of these are aspects of climate change that usually have many, often interacting causes.
The politicians and their spin-doctors were clever. They dropped global warming in favor of climate change when they realized that the consensus view of global warming held the anthropogenic label. Better for them to widen the discourse.
So instead they began to add an adjective and began talking of dangerous climate change or catastrophic climate change… that is another story.
Objectively to decide which of the two terms to use we should confirm that global warming is actually happening. And this is not as easy as ot sounds.
Meantime it is also best to think and talk of climate change as both warming and cooling given that is what it is.
Environmental Issues for Real by Dr J. Mark Dangerfield looks at some of the obvious, and some of the not so obvious, challenges for a growing human population living as we do in a finite world.
Only this time it's not about the impending disasters or the guilt or the blame.
This time, it’s 10 brief essays that are about the bigger picture. In less than an hour you could glimpse something different, a view that we can only see when we take a fresh look.
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