Melvyn Bragg and
his guests discussed ice ages, periods when a reduction in the surface
temperature of the Earth has resulted in ice sheets at the Poles.
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The 6,000 km plus journey of the India
landmass (Indian Plate) before its collision with Asia (Eurasian Plate) about
40 – 50 million years ago.
|
Although the term
'ice age' is commonly associated with prehistoric eras when much of northern
Europe was covered in ice, we are in fact currently in an ice age which began
up to 40 million years ago.
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Fossil patterns across
continents (Gondwanaland).
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Geological evidence
indicates that there have been several in the Earth's history, although their
precise cause is not known. Ice epochs
have had profound effects on the geography and biology of our planet.
From this BBC radio
programme “In our Time” I learnt some things I hadn’t realised and with the
interest we have in the earth today, the technologies that are allowing us to
explore and find out more ... I thought I’d highlight a few aspects I found
fascinating ...
The
earth is about 4.55 billion years old, during which there have been five major
epochs conducive to the growth of ice at the poles.
In
between - the ice comes and goes – sometimes for long periods of hundreds of
thousands of years, at other times over a slightly shorter time frame of only
tens of thousands of years.
The
term ‘Ice House Earth’ is used when there is glaciation on one or both poles –
it is estimated that this has occurred for about 15% of earth’s existence, and
where we are now – a propitious time for the human being as we know him.
 |
A geographical map of Africa,
showing the ecological
break
that defines the Saharan
area.
(Wikipedia: Sahara)
|
The
other 85% of the time this earth planet has been in the Greenhouse inhospitable
state ...
I had
no idea that Gondwanaland (the huge landmass of five joined ‘southern’ continents) sat over the South Pole
– glacial evidence is to be found in the Sahara...
...
while the northern hemisphere landmasses, where the coal fields are now found,
used to be in the tropical belt around the equator; from where the lush forests
were able to grow in that warm tropical environment.
The
shifting tectonic plates leave marks in the glacial moraines on the rock
platforms giving geologists their evidence, while the seas and oceans back up
and provide further developmental evidence of these changes to the earth.
 |
Boundary for 20 degC isotherms.
Most corals live within this boundary.
(Wikipedia: Coral Reef for more info)
|
The
sediments at the bottom of the ocean give us a valuable archive of past
climatic activity – the records are continuous and can be dated – providing
scientists with a ‘laboratory’ for the continuing collation of evidence.
Coral
reefs provide recent evidence, but also those reefs preserved in the sedimentary
layers hold historical evidence ... as corals
only grow at temperate sea level they reflect these sea level
changes ...
... giving
us a ‘tidal mark’ in the passage of time, as the ocean levels rise and fall,
and the fact that the continents had drifted away from the temperate regions.
 |
North Sea: showing northern Europe and the
British coastline – Dogger Bank in red is a large sandbank that probably was a
moraine ... and formed one of the land links from Europe to Britain; the
English Channel could also be walked across.
|
... the
oceans and seas are a recorder as well as a connector between the rest of the earthly
land masses ... the continents continued to move – and as they did the ice
slowly melted ... or froze up again ... the earth is in a constant state of
change ...
... as
an ice sheet grows it locks up the water from the oceans, so the sea level will
fall ...
...
20,000 years ago the sea was 100 metres lower than today (at the last glacial
maximate), but 125,000 years ago the sea level was about 5 – 6 metres higher
than it is today ....
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| Getting set to go on April Fool's Day - A - Z Challenge here we come! |
20,000
years ago the United Kingdom was connected to the main land of Europe – when
dinosaurs walked the earth ... and as man was starting to inhabit these
northern environs ...
This
will take us into my next few posts before the A – Z challenge ... man walked
the earth – how and why did he get where he is today ...
Life is
so interesting ... the coal forests of North America, the UK, northern
Europe/Asia and China were formed in the tropics; while Antarctic explorers
might have been ‘chasing’ deserts; then if those ice epochs had not occurred
... would we be here at all ...
Hilary
Melton-Butcher
Positive
Letters Inspirational Stories
58 comments:
So the North and South Poles are only covered in ice fifteen percent of the time? Wow, didn't know that.
I have been paying a little attention to all of this quite recently when there was all the talk of Planet X crashing into earth or whizzing by close enough to cause a pole shift. It's all very fascinating. More education, thanks Hilary.
Thanks Hilary, interesting post and I learnt several things here I did not know. Have a good week and take care Diane
Learn something new everyday.
~Summer
I read something recently that said that the south pole is a "frigid desert" and that it actually rarely gets snow. The snow there never melts so the snow on the ground has been there for ages. Crazy eh?
Very interesting and informative post, Hilary
It's fascinating how little we know or understand about this ball of mud we sit on. Sounds like our greenhouse effect is inevitable, no matter what we try. I makes me wonder if humans will persevere in the long run - or go by the way of the dinosaurs.
Amazing how much the continents travel too!
I didn't know that the ice had such an impact. It explains the weather and why it's so crazy. Can't wait to read the next three parts.
@ Alex - the whole earth had ice on it for 15% of that time and we're in a particular % time frame now - the rest of the time is hot-hot-earth in a serious uninhabitable way ...
@ Manzanita - it's putting the whole into context ... I sort of do that here - but I'll add a note about the recent comment in the wrap up (part 4) ...
@ Diane - it was an interesting post to write ..
@ Summer - we certainly learn all the time ..
@ Keith - I didn't pick that up ... but that's an interesting addition to the post - as you say ... 'crazy' - strange but true.
@ Bob - many thanks ...
@ Karen - we are such microscopic parts of this planet ... in an even smaller percentage of time ...
@ Laura - more like this bubbling volcanic furnace temperature gooo ... and yes I think whatever we do - is overridden by nature's forces ... and we may well go the way of the dinosaurs ...
I hadn't thought about the continents moving along on their tectonic plates quite so much ...
@ Clarissa - the weather too - in all its layers affects life on earth and thus the appropriate conditions for ice to form ...
Thanks everyone for your excellent comments - Hilary
Yes the face of the globe has changed, continents have separated or come together. Now we are able to know all this. When I was a child I didn't even know the weather of the neighbor town, lol !
Yes it is all so interesting .
If we only knew what the past held
we would not be so paranoid with the present and future.
I love the new possibility of having a lasered elevator taking us up into space.
One space station connected to another till we reach mars or the moon.
Wouldnt that be something to live for to see?
You educate many of us bloggers.
Reading of ice today I am in the heat of Spain visiting my youngest son, Here until Friday.
Thanks for a most interesting read,
Yvonne.
I feel so small after reading this. Our Planet is amazing. Long time ago, my grand mother's friend used to tell a story of a place where there was six months of night and six months of day. We used to think of it as a child's fantasy.
Not too long ago, this year, a man was swallowed by Earth they said. In Florida there are places where one of the layers of the Earth simply gets depleted and thus the next layer falls in like trying to fill a gap. Therefore, whatever happens to be in that little bit of the land falls in. Sadly, the gentleman was not rescued. Now they are locating similar "Sink Holes" in the area to prevent such tragedies.
Fascinating post, Hilary. Kinda makes one wonder if the whole "global warming" concern is much ado over something over which we, in reality, have little control. I'll be looking forward to your next installments.
I don't understand why they don't teach us this stuff in school. This was fascinating. Makes sense, too! Thanks, Hilary!
I actually minored in geography in college and love reading about this stuff. Yeah, we've gone through different epoch periods of ice and heating, but none in the past compare to the scale and speed at which we're warming now. One thing about our planet, though, it wants balance. It's what drives weather (polar ice vs equator). If we can stop spewing the carbons in the air (which absorb heat) we might see nature correct itself over time.
We recently watched some British programmes on this kind of stuff. It's absolutely fascinating isn't it? I hadn't realised the Channel didn't exist, why not I don't know. I learned that on TV. I have also learned several new things from you today. Keep up the good work Hilary.
Enjoyed your A to Z last year, looking forward to what you do this year. Hadn't registered it starts on April Fool's Day.
JO ON FOOD, MY TRAVELS AND A SCENT OF CHOCOLATE
So when this ice age finishes up we'll be toast, quite literally. I think luck has played a big part in how we got to where we are today. Thanks for the informative post!
I love history but I find prehistory confusing. How do they know when the land masses drifted? How do they know about previous ice ages and are we approaching another ice age or moving towards a period of global warming? I wonder if they know the answer to that.
If this is your A-Z theme, I can't wait. I love this stuff. I think I'll tell Al Gore to take a look at this information.
Great post as always, Hilary.
Interesting. I hope the ice will not continue to melt... the sea level is rising.
Hi HIlary,
Reading your blog is much more fun than reading National Geographic! You must spend a lot of time researching! Quite enjoyable!
Hugs
Suzen
That was amazing - do you just pick a topic and then research it - or do you somehow know all this facts - I am shocked and amazed at how much I didn't know. Very interesting. sandie
Greetings Hilary,
My human is trying to warm up as this winter seems to just go on and on and...
Anyway, your meticulous detail to this important topic is duly noted.
Many worrying signs out there. The polar bears can vouch for that.
Thank you for this enlightening article, Hilary.
Pawsitive wishes,
Penny
@ Gattina - as children as long as the sun shone we were happy and we had night and day and the 4 seasons .. something's happened since!
@ A Lady's Life - your take on the future needs a stable earth .. and I'm not sure we have that!
@ Yvonne - good to see you .. and glad Spain is warm.
@ Munir - the earth is incredible I agree .. but constantly altering by the force of nature usually, and the passage of time - as that chap in Florida sadly found out.
@ Susan - I think you've hit the nail on the head ... it's beyond our control.
@ Joylene - thanks so much ... I broke the whole thing down to the basics ... so good to know it makes sense to you.
@ Luanne - I loved Geography at school ... when we come out of a real ice age the 'event' speeds up (at the end) and it looks like we might be there now.
However - we may well be going back into another ice age ... the ocean currents are changing dramatically and this could cause us to freeze over once again ...
It's interesting and what you're saying makes sense .... yet ....
@ Jo - we keep forgetting so much of our continental land masses have split asunder .. there's so much evidence of dinosaurs, early man, woolly mammoths etc in the muds of the north sea .... some tusks found only the other day - near your old homeland in Kent ...
The A-Z always starts on April Fool's Day .. strikes me as "crazy" too!!
@ Nick - I think we may be frozen (bread) slices ... but we don't know - and your thought that luck puts us where we are today is probably right. But I love learning the hows and the whys ...
@ Ros - so much information is available via scientific discovery ... the technical details possible were to a point explained in the Melvyn Bragg "In our Time" talk that I took a great deal of this info from.
The scientists explained a great many aspects ... and various presenters such as Dr Iain Stuart, Professor Brian Cox etc ... their knowledge is prodigious ..
In my own mind we might be going back into another ice age ... global warming is a precursor ...
@ Lee - No this isn't my A-Z theme ... something lighter! Many thanks ... Al Gore would be a little baffled reading this summary I suspect!
@ Julia - it may melt and then freeze over ... none of us know ...
@ Susan - I try and make things as easy to understand for me, and then, thank you, I hope you can grasp the ideas too ... seems to work so far!
@ Sandy - this time I heard a talk, which I found fascinating = this post; then the next two stemmed from a tv programme (which seemed to tie in) .. and the last will be some form of summary - delighted you enjoyed it ...
@ Penny obo Gary - are your paws freezing again: it is really horrid isn't it .. just so cold and miserable and today is the first day of the Spring equinox - when the days are slightly longer than night!
I empathise with Gary .. it is really chilly .. however the polar bears have a worse time than we are - we just don't make their life easier .. taking their natural roaming areas away ...
Thanks everyone it's always wonderful to read your comments and find you're enjoying the posts - lovely! Cheers Hilary
Interesting as always, Hilary.
It's strange to think the land is moving all the time.
This is so interesting. Right now, I think Missouri is heading into an ice age.
Your posts always teach me.
Oh Earth!! What a history!! Amazing how the continents shifted (literally) to create other continents!
Take care
x
Thanks Hilary. Great post! My brain feels fed with something that will stick to my ribs. Okay, that made no sense, but its very early here and I have to finish my first cup of coffee.
Sorry, Hil. Blogger has been eating my comments all morning, so instead of pasting my signature, I pasted my comment to Lee's post...I've been copying each comment before I post it so that I can at least re-try. Anyway...here's YOUR comment.
Loved this. With all the focus on global warming/climate change/carbon credits, etc. it's refreshing to just get some plain old provable FACTS. I'm really looking forward to the rest of your series.
Tina @ Life is Good
Co-host, April 2013 A-Z Challenge Blog
@TinaLifeisGood, #atozchallenge
@ Patsy - yes .. do you feel you're helter skeltering towards me when you drive east - tipping slowly into the sea?!
@ Teresa - oh gosh, well I think we seem to get your weather after a while - and really I could do with a warming Spring! Delighted you enjoyed the post .. thanks.
@ Old Kitty - I'm always incredulous at what happens to the earth ... so much movement but over aeons of time ... I'm hanging on and hope I don't fall over the edge!
@ Stephen - well if something stuck that early in the morning ... I must have done something right here!
@ Tina - no worries .. and I have that irritating trouble occasionally with Blogger.
Just delighted you appreciated the plain speak ....
Thanks so much to you all - it is sunny here - but cold out there .. the snow is staying in the north ..
Cheers Hilary
Great post. The shifting of our land masses have long fascinated me.
Hilary, you have chosen a fascinating topic for A to Z. I can't wait to read more!
Most interesting! We are riding on top of a big marble, constantly changing.
It's amazing to think what an impact ice had on our existence...and how it ties into our existence today. Protecting those polar ice caps seems most important.
I know they've found mammoths in Antarctica with green food still in their mouths--like they were flash frozen. There is lots of evidence of tropics where, today, it's not.
The earth tells a fascinating story, doesn't it?
interesting speculations & assumptions =)
i like hearing how some conjecture on our origins!
Hilary,
I enjoyed learning all the things you've learned, as always.
I was taken back by this: "glacial evidence is to be found in the Sahara..." Oh. My. Gosh...that's amazing.
Is the A to Z challenge of "man walked the earth -- how and why did he get where he is today..." your challenge or the challenge for anyone?
I'm looking forward to this. Keep your fingers flexible:~)
@ Holly .. it just interests me and if I can make some semblance of sense - I'm grateful!!
@ Theresa - no this isn't my A- Z topic! It's still under wraps .. but I'm sure you'll enjoy my choice ..
@ Rosaria - yup - those tectonic plates are doing their thing, and we just go along for the ride ... you're so right!
@ Elizabeth - ice has always been around and we forget .. north of London was glacier bound .. and where I am I could walk to France - and oh what a lot of money it would save .... not sure my little bones could survive though!!!
I'm not sure we can do much about things ... too many different perspectives ... BRICK v us lot etc .. we're all at different development levels - and would it make much difference ... I'm not so sure ...
@ Sia - oh I hadn't read that .. it does sound like very FAST FREEZE doesn't it ... poor mammoth ..
It just fascinates me to think the Sahara could have spent time down in Antartica ...
Fascinating world ---- as you say!
@ Tara - yes it's science ... so not set in stone - but I'm sure a great deal of it is fact ... as far as they can tell ...
Like you conjecture (reasonably scientific) is interesting to me ..
@ Sara - thank you! I know things I'm sure I might have been aware of - but hadn't taken cognisance of ..
uh uh - the A-Z for me is under wraps for 10 days .. but I think you'll enjoy it ... this year's A-Z will be easier for me .. the Castles last year were enormous fun, hard work, but I know everyone enjoyed them ... so the hard work was worth it ...
Cheers to you - I do so appreciate your thoughts and comments ... Hilary
Here in Castle Pines, Colorado, where I live was a huge rain forest, the largest in North America and our water, as our water department like to tell us, comes from a large aquifer the water of which at one time washed over the backs of woolly mammoths. Especially looking forward to your A-Z blogs, 2013.
This is all fascinating stuff. You've done a lot of work to bring the information to us. Thank you for that. I can't wait to see the next part on how man first appeared. The BBC recently published an article about Neanderthal man being smarter than we once gave him credit for.
You really think we're heading for another ice age? I thought we were warming up because in the 19C they had fairs on a frozen Thames etc. but then I truly believe that none of the scientists really know for sure. There have always been temperature swings but how far each swing goes doesn't seem to be calculable. It's all fascinating stuff... but I do get a tad anxious about it too!
@ LoverofWords .. well at some stage I'm sure that forest was over the tropics. Castle Pines sounds a lovely description ... there must be plenty of ancient aquifers around North America. Lots of space for Woolly Mammoths to roam! Thanks re the A-Z ... I'm going to enjoy it too.
@ Francene - yes there's been more scientific aspects come to light recently .. and I'm sure they'll find out so much more ...
Cheers and thanks for visiting .. Hilary
Hi Ros .. I sort of think so - but what do I know! The thing that I'm fairly sure about .. there's not an awful lot we can do - so I don't worry. In future generations .. we've adapted before ... but I am sure we're living in very propitious times and we're very lucky ..
Enjoy the weekend - looks like freezing cold and snow in your part of the world (Leicester) ... cheers Hilary
"Life is so interesting" you say - yes isn't it?! I love the way you give us all these facts, half of which I was not really aware of. We reap the rewards of your research I feel. I will not be joining the A-Z challenge since I can barely get from A-B at the moment in my head but I will be checking out yours Hilary :-) Debbie X
Fascinating Hilary and I enjoyed reading this so much. I just heard a fellow speak (from Yale University) about how we are going to teach about Climate Change and Global warming to the people so that they can respond before it is too late, we are at the edge of where we can make a difference and possibly turn it around or slow it dramatically.
The main difference about climate change happening right now - is that beyond a doubt this is HUMAN MADE...
Thanks for sharing this
Fascinating. There's always the experts that say we're going on way or the other. I do wonder what the world would do if we got cold instead of hot.
I remember learning about plate tectonics, the continental drift and how the different continents used to fit together. I was truly amazed. Actually, I still am.
Not much we can do about the changes that will take place, but go with the flow, literally, if you live near water.
Thanks for this very intriguing article. I love learning new things daily.
Looking forward to the A to Z Campaign again this year.Have a great week.
@ Deborah - many thanks for taking the time to visit ... your life has been distinctly full on - and I do hope 2013 becomes slightly easier for you. I hope you enjoy my A-Z .. I think you will! Look after yourself ..
@ Patricia - the more people become aware of what happens in the world .. I'm not sure we, as humans, can make a difference, we can help ... but nature is its own mistress ..
We've messed around with things .. but nature is nature and will happen anyway ..
@ Christine - it may go both ways ... warmer first then colder for longer - who knows! Running away won't help though ....!
@ Elise - I so agree with you .. I was always amazed at the numbers of flora and fauna that can be found on different continents having evolved its own species.
@ Kathy - good to meet you .. thanks for coming by ... and you too, the A-Z will interesting and fun I hope. Water levels are rising ... but then what? Erratic weather seems to be the order of the day though ...
Thanks everyone - so lovely to see you ... cheers for now - Hilary
Interesting stuff. There are many things about the earth we don't know, and may never know.
Thanks Diane .. I'm sure you're right - we will probably never know much of life and how it happened - still it's interesting to learn as you mention ... Cheers Hilary
That sounds like an incredible series...hopefully it will play here eventually. The earth is truly a wonder...
Hi Talon .. this one is a radio discussion and is still up - perhaps not in the States ... However - the earth does amaze - just wish it would stop raining or snowing for a few months! Cheers Hilary
I'm fascinated by the changes of our planet. To me, it proves global temperature changes are less to do with us and much more to do with how it's always been. We might be accelerating it a bit, but we're the only ones who will suffer - our planet has suffered much worse!
Lots of interesting theories here Hilary! I agree that we will just have to hope for the best.
Julie
@ Annalisa - yes, I agree ... global changes will happen and that we're helping a tiny tiny bit - and the planet will survive ... this species, us humans, is another matter ... I think we're on the same wave length ..
@ Julie - we should be alright .. it's the generations afterwards ... we live in interesting times ..
Cheers to you both .. Hilary
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