It is often assumed in many media reports that:
- All the mountain glaciers on earth are melting and receding rapidly
- They will all vanish in a few years
- This is an unprecedented change in the Earth’s (and hence mankind’s) environment
- This is entirely due to the effects of modern industrial civilisation, particularly increased air and road transportation
This topic seems to be coming up an awful lot these days and I’ve posted some lengthy blogs about this already – see ‘Is global warming really caused by human activity?‘ and ‘The global warming debate, the scientific method, fortean philosophy and the paranormal, and the Iraq war‘. I’m now prompted to write some more about this after some of my recent mountain walks and two recent news articles that appeared on the BBC news website.
The first BBC news article can be seen here and details research that ostensibly provides a solid scientific rebuttal to the claims made in a recent UK television Channel 4 documentary about climate change (which I and others have discussed at length in a blog posting here) being caused by solar output, and bolsters the orthodox scientific view that the current warming of the global climate is being caused by mankind’s recent activity. The second BBC news article can be seen here and details some scientific research carried out on the Greenland ice-cap. This research seems to suggest that the Greenland ice cap is much more resistant to disappearing in a warming climate than previously thought, but it was this quote from the news report that really made me stop and think:
“Studies suggest that even during the last interglacial (116,000-130,000 years ago), when temperatures were thought to be 5C warmer than today, the ice persevered…”
This means that thousands of years ago, the climate was warmer than it is now – and it was an interglacial period. The greenland ice-cap did not disappear during this period, and in fact it started to get bigger again when the interglacial period came to an end. We are in another interglacial period right now, that is still actually colder than the previous one mentioned in the news article, when there was no human industrial civilization around. The only conclusion one can draw from this is that the earth’s climate changes naturally, and it has always changed in irregular cycles of cooling and warming. The Earth’s climate has changed in this way many times in the past with no human activity around to affect it.
A similar example that I have mentioned previously is the glacial ice on the summit of Mount Kilimanjaro (see the blog postings ‘Scottish glaciers’ and ‘Has climate change already affected hillwalking in Scotland and further afield?’). This ice started disappearing in the 19th century, before human civilization and mass transportation started producing large quantities of greenhouse gases, and in fact many theories suggest that the ice disappeared completely a few thousand years ago, only to come back again.
So who is right about the causes of the warming climate? What we have here is a situation in which two groups of respected scientists have effectively come to contradictory conclusions, and my opinion about this sort of inconclusive debate amongst ‘experts’ (that I articulated at the end of the posting ‘The global warming debate, the scientific method, fortean philosophy and the paranormal, and the Iraq war‘) is still the same: no-one seems to really know for sure.
The orthodox scientific consensus that the current warming trend in the global climate is caused by mankind’s recent industrial and transportation-related activites is not as strong as the media, politicans and environmental activists almost always portray. There remain unanswered questions about this untested hypothesis and the only incontrovertible experimental environment in which to test this hypothesis out in is the entire Earth system – and the outcome of this experiment will not be known for 50 years.
There is more on the BBC news website about the last interglacial period here:
Some scientists now think that polar bears survived this interglacial period, despite temperatures then being even warmer than they are now.
The BBC news website has an article about a period 4000 years ago and its effects on the Greenland ice sheet:
“Four thousand years ago, the Earth was significantly warmer than it is now”
It’s worth repeating that this happened without any human industrial civilization around to cause it.