Climate Change, it's not a new topic. We knew about this issue 30 years ago — at least I and my senior students did. Since then, there's been much burying of the nations' heads. I include Canada, which under of former government, led the world in head-burying.
The science is very simple, at least if ordinary plods such as myself keep it that way.
Simply put: natural CO2 and other gases along with clouds in the atmosphere are what heat us up by retaining heat before it can eventually escape into space. When we add tons and tons of CO2, we trap more heat in the atmosphere for longer before it is lost into the great beyond. It's not a difficult concept.
I liken it to switching from a sheet to a blanket on a cool night. In itself, the blanket is no warmer than the sheet, but it sure is better at holding the heat in. It is our own retained heat that keeps us warm. If we get too warm we kick off a covering layer to cool down. We now need to kick off the extra covering that we are putting into the atmosphere.
The following graph shows that we have much more CO2 in the atmosphere than we have had for 400 000 years, and it is indisputable that we pump billions of tons of CO2 into the atmosphere every year. Yes, billions. (link)
As a result, temperatures have already increased by about 1.53°F (0.85ºC) from 1880 to 2012.
The deniers like to say that the climate has always changed, alternating between warm and cool periods.
Well yes, but if you track those changes in the same time period (400 000 years) as the chart above, it always gets warmer when CO2 levels increase. And humans are increasing the CO2 levels beyond the rise that we should normally expect in this natural warming cycle. The other point is that in natural circumstances the increase takes place over thousands of year not in a hundred years or so, which is what is happening now.
The last spike in CO2 and temperatures occurred about 120 000 years ago (see graph, above) and seems to have lasted for perhaps 40 000 years. This caused much glacial melting and a rise in sea levels. Sea levels are presently rising again.
When the seas rose back then, we didn't have many millions or people living on low lying coastal plains. In fact, there were no people to speak of. If sea levels rise dramatically now, it won't be good for New York or Florida or The Netherlands or Bangladesh and so on. You get the idea.
Climate Change is not a figment of someone's imagination but is based on a convergence of all sorts of observational data. This is called consilience as data from "pollen, tree rings, ice cores, corals, glacial and polar ice-cap melt, sea-level rise, ecological shifts, carbon dioxide increases, the unprecedented rate of temperature increase" (link) all support human-induced Climate Change.
And that, folks, is my short and simple foray into the realm of science, except to say that, according to surveys, this science is supported by 97% of scientists in this field, and it also seems that many of the 3% happen to have a vested interest in denying that there is a problem.