It's MUCH more than "speculative" say virtuall ALL THE WORLD RENOWN SCIENCE AGENCIES.<quoted text>
a) real and severe consequences (minimata disease, ozone depletion, dead lakes in the Northeast) were being demonstrably and inarguably experienced in the immediate present, not speculatively 50 or 100 years down the road,
Here is NASA stating how we know:
Here is the ROYAL SOCIETY of England and this is typical
<<It is certain that increased greenhouse gas emissions from the burning of fossil fuels and from land use change lead to a warming of climate, and it is very likely that these green house gases are the dominant cause of the global warming that has been taking place over the last 50 years.
Whilst the extent of climate change is often expressed in a single figure - global temperature - the effects of climate change (such as temperature, precipitation and the frequency of extreme weather events) will vary greatly from place to place.
Increasing atmospheric CO2 also leads to ocean acidification which risks profound impacts on many marine ecosystems and in turn the societies which depend on them.
The Society has worked on the issue of climate change for many years to further the understanding of this issue. These activities have been informed by decades of publicly available, peer-reviewed studies by thousands of scientists across a wide range of disciplines. Climate science, like any other scientific discipline, develops through vigorous debates between experts, but there is an overwhelming consensus regarding its fundamentals. Climate science has a firm basis in physics and is supported by a wealth of evidence from real world observations.
The problem is the OIL and COAL companies are starting a misinformation
campaign on global warming.
Here is Scientific American:
<< There is, in fact, a climate conspiracy. It just happens to be one launched by the fossil fuel industry to obscure the truth about climate change and delay any action...
As physicist and climate historian Spencer Weart told The Washington Post: "It's a symptom of something entirely new in the history of science: Aside from crackpots who complain that a conspiracy is suppressing their personal discoveries, we've never before seen a set of people accuse an entire community of scientists of deliberate deception and other professional malfeasance. Even the tobacco companies never tried to slander legitimate cancer researchers." Well, probably they did, but point taken.>>