Global Warming

[rov1100]

http://www.bbc.co.uk/...-environment-15373071

Is there a limit to how much the atmosphere will heat up and rise to a plateau?

[Old_Geezer]

I guess it'd find it difficult to match the atmosphere on Venus.

[beso]

Eddie's tale is somewhat confused. While some agriculture was undertaken for a short time by Norse settlers during the Medieval Warm Period, Greenland was certainly not farmed in pre-Roman times.

Note that the Medieval Warm Period was a regional anomaly mostly affecting the North Atlantic and especially the North American continent. It was probably due to changes in the North AAtlantic Thermohaline Circulation. Many other areas of the globe were cooler and the average global temperature was lower than it is today.

The Coniferous Period?? Perhaps he means Carboniferous Period though this was known for coal deposits rather than oil. The largest oil deposits came later during the Mesozoic Era.

These periods were hotter largely due to the much higher atmospheric carbon dioxide levels.

[rov1100]

There seems to be a lot of conflicts about the causes of global warming and to quote what happened to cause it going back many centuries leaves us none the wiser.

If we look at the graph shown in this article it took 130 years from 1810 to 1940 to rise one degree.

A more recent study from 1970 to 2005 (just 35 years) to raise by the same amount. ie in nearly a quarter of the time.

With all the brains studying this rise you would think a correlation would stand out. ie is there 4 times as much CO2 in the amtosphere as before?

[jake-the-peg]

You'd think there would be a sudden rise - if it were a simple system.

However as we all know weather systems and climate are very much not simple systems.

The models that predict climate change are cutting edge computer simulations running on super computers.

It's not a case of you double this and that doubles

[Davethedog]

Eddie "that the increased CO2 levels (mainly man made) are to blame"???

http://www.skepticals...natural-emissions.htm
http://www.geocraft.c.../greenhouse_data.html

As more and more is researched man is found to be less and less to blame however there is a green agenda that is making billions of pounds per year.

[jake-the-peg]

This is similar to a skeptic argument you hear sometimes

Below is a page explaining it and why it's wrong or rather badly misleading

http://www.skepticals...ature-correlation.htm

[BillyBB]

Rov, beyond a certain level further increases in CO2 will hardly increase the greenhouse effect of our atmosphere. So yes there is a limit, there is also a limit to possible temperatures on earth because we get a finite (although variable) amount of energy from the sun.

Relevant phrase on that link being 'solar minimum' the sun being the primary driver of our climate, temperatures and weather and any variation of such.

Medieval Warm Period was also recorded in Japan, not exactly North Atlantic.

Bit harder to explain the Pliocene warm temperatures when CO2 levels were no higher than today but the oceans certainly contained much much more heat.

Even the IPCC admits that the models they touted in the eighties, then the nineties, were rubbish and do not stand backward scrutiny. Doesn't matter how cutting edge your computers are, the results will always come closest to that which will generate more funding. And we have seen now what a hodge podge some of the programming is never mind how they filter the data going into them.

[beso]

The models are continually being improved by factoring in more and more variables. They have always predicted a rise in temperature and the match with the geological record is increasing accurate as they develop.

The sun is a driver of climate fluctuations but it is only one factor. The long term measured temperature changes are not correlated to the solar cycles.

Yes the Medieval Warm Period was experienced in various locations around the planet but most strongly in the North Atlantic. Pacific Ocean currents were also affect. However it was not an increase in average global temperatures. Large parts of the plant were cooler than todyay.

"During the Pliocene the earth climate system response shifted from a period of high frequency-low amplitude oscillation dominated by the 41.000 year period of Earth's obliquity to one of low frequency-high amplitude oscillation dominated by the 100.000 year period of the Orbital eccentricity characteristic of the Pleistocene glacial-interglacial cycles."
http://en.wikipedia.org/wiki/Pliocene_climate

Those who don't accept that we are having a profound effect on the planet's climate are deluded.

The claim that there is a limit on temperature rise shows profound ignorance. Morover a rise of a couple of degrees will cause a massive change to the environment.

The claim that the increased CO2 is not from man is completely wrong and that can be proved. Fossil carbon produces carbon dioxide with virtually 100 percent Carbon 12 and that is exactly what we see in the atmospheric CO2 increase.

[beso]

In fact at about 400ppm, Pliocene CO2 levels were only slightly higher than today. However with an annual growth rate at about 2 ppm we will be there well before end of the decade.

The Pliocence was about two to three degress warmer than today. However due to the rapid rate of change we are experiencing a climate far more like a long term CO2 level far below what it is now. Preindustrial levels were about 280 ppm.

The sun is considerably hotter now than it was in the Pliocence so even at the CO2 levels we will reach in the next few years we ultimately can expect to expereince temperatures considerably warmer than the Pliocene. Sea levels then were 25 metres above today.

Far from being a case against the need to act on global waming, the Pliocene is backing the climate models' predictions.

Wake up fools. The science is clear.