March 7, 2013 at 11:57 pm #257656
“Earth on track to be hottest in human history: study”
Earth is on track to becoming the hottest it has been at any time in the past 11.3 millennia, a period spanning the history of human civilisation, a new study says.
Based on fossil samples and other data collected from 73 sites around the world, scientists have been able to reconstruct the history of the planet’s temperature from the end of the last Ice Age around 11,000 years ago to the present.
They have determined the past 10 years have been hotter than 80 per cent of the past 11,300 years.
But virtually all the climate models evaluated by the Intergovernmental Panel on Climate Change predict Earth’s atmosphere will be hotter in the coming decades than at any time since the end of the Ice Age, no matter what greenhouse gas emission scenario is used, the study found.
“We already knew that on a global scale, Earth is warmer today than it was over much of the past 2,000 years,” said Shaun Marcott, the lead author of the study, which was published in Science.
“Now we know that it is warmer than most of the past 11,300 years.
“This is of particular interest because the Holocene spans the entire period of human civilisation.”
The data show that temperatures cooled by 0.8 degrees Celsius over the past 5,000 years, but have been rising again in the past 100 years, particularly in the northern hemisphere where land masses and population centres are larger.
The climate models project that average global temperatures will rise by 1.1 to 6.3 degrees Celsius by the end of the century, depending on the level of C02 emissions resulting from human activities, the researchers found.
“What is most troubling is that this warming will be significantly greater than at any time during the past 11,300 years,” said Peter Clark, a paleoclimatologist at Oregon State University.
Earth’s position with respect to the Sun is the main natural factor affecting temperatures during that time, the scientists said.
“During the warmest period of the Holocene, the Earth was positioned such that northern hemisphere summers warmed more,” Mr Marcott said.
“As the Earth’s orientation changed, northern hemisphere summers became cooler, and we should now be near the bottom of this long-term cooling trend – but obviously, we are not.”
Other studies have concluded that human activities – not natural causes – have been responsible for the warming experienced over the past 50 years.
AFPMarch 8, 2013 at 12:09 am #531433
This thread is about anthropomorphic global warming, about human interference with the planet’s natural “Greenhouse Effect” and the established “science of global warming” thereof. This thread is also about new information that further informs us “scientifically” about these matters.March 8, 2013 at 12:15 am #531434AndreKeymaster
Yes .. so be warned all .. happy for you to agree or disagree, but please show us something to back your views up. Any posts that simply denies the content of thread, will be deleted. The same with posts going off-topic.
I better repeat that:
Any posts that simply denies the content of thread, will be deleted.
We’ve all been down similar roads before – we know where it’s headed if we don’t keep a tight reign on this.March 8, 2013 at 12:19 am #531435
Here’s a story about the same scientific study at sciencedaily, it’s got a bit more detail than the ABC news story.March 8, 2013 at 2:37 am #531436BlueWrenMember
Thankyou Bullseye. Excellent information.I feel the heat, and I really do think it has been even more unpleasant in the last few years, especially this last summer.March 8, 2013 at 10:04 am #531437RegetiusMember
Here is an informative (and scary) talk on global temperature rise and its effects.March 8, 2013 at 12:33 pm #531438
BlueWren post=354320 wrote: ….I really do think it has been even more unpleasant in the last few years, especially this last summer.
The latest report by the Met Office in the UK shows the global average temperatures haven’t changed for the last 17 years. Of course it might have been warmer where you are, and some locations will be hotter than average, some cooler than average, but on the global scale warming seems to have come to a standstill.
See the graphs here: http://www.metoffice.gov.uk/hadobs/hadcrut4/diagnostics.html
There’s a rather telling quote from one of the scientists:
“Prof Jones also admitted that the climate models were imperfect: ‘We don’t fully understand how to input things like changes in the oceans, and because we don’t fully understand it you could say that natural variability is now working to suppress the warming. We don’t know what natural variability is doing.”
This is what I’ve been saying all along – the climate system is extremely complex and they don’t fully understand it and can’t model it perfectly, as they themselves admit. CO2 is just one factor that affects climate, which is why we can get a pause in global warming for 17 years even as CO2 levels have continued to go up.
The “debate” is also nowadays a political one – the science isn’t out of the window exactly but it’s hard to find among all the political “spin” (ie. propaganda). There’s been a notable absence in media reporting of the 17 year pause in global warming in Australia because the media only reports the “accepted” view – probably because scaring people sells more papers.March 8, 2013 at 12:58 pm #531439BobbeeMember
Well we are having a 36 degree day and this is Autumn. Not just one day either but more than a week of above 30 degrees. That is a hot Autumn in my books. I hope the weather report is scientific enough for this thread, apologies if that is not what you have in mind Bullseye.
But that’s about as scientific as I get by myself. So thanks for the links, they are most informative and I appreciate them.March 8, 2013 at 11:15 pm #531440
Weather and climate are two different things. It is hotter now in some places than it has been before, but it’s colder in other places than it has been before. In most places it’s the hottest since… or coldest since…. Globally, it hasn’t been warming overall, according to the figures, for 17 years.
BTW It’s hot here too and I think we’re on the 8th day of unseasonable hot weather, and I am so SICK of being hot!March 9, 2013 at 9:41 am #531441
Regarding the “Met Office Hadley Centre observations datasets”. A “line of best fit” (google if you don’t know what that means) indicates significant global temperature rise, simple. Interpreting the data in another way to “best fit” a belief or whatever else means very little in real terms or scientifically.
Something of interest below…
Welcome to the Eco Audit
Yesterday, the Met Office published a press release confirming that it had recently revised downwards a decadal global temperature prediction for the period up to 2017. It said it had been prompted into issuing the release following “media coverage” of the adjustment, something it had published without fanfare on its website on 24 December.
The adjustment was first spotted on 5 January by a poster called “Duwayne” on the SolarCycle24.com web forum. Climate sceptic bloggers soon picked it up and on 7 January Roger Harrabin, the BBC’s environment analyst, tweeted that the Met Office had confirmed to him that it had cut its warming projection for the period up to 2017 by 20%. He followed it up yesterday with a brief item on the BBC Radio 4’s Today programme, which, in turn, was later fleshed out by David Shukman, the BBC’s science editor, in an article on the BBC News website [the article was amended by the BBC on 10 January to correct the second sentence; the quote below reflects that change which stresses the projected rise is marked against the long-term average as opposed to present day]:
The UK Met Office has revised one of its forecasts for how much the world may warm in the next few years. It says that the average temperature is likely to be 0.43 C above the long-term average by 2017 – as opposed to an earlier forecast that suggested a warming of 0.54C.
The explanation is that a new kind of computer model using different parameters has been used. The Met Office stresses that the work is experimental and that it still stands by its longer-term projections. These forecast significant warming over the course of this century.
The forecasts are all based on a comparison with the average global temperature over the period 1971-2000. The earlier model had projected that the period 2012-16 would be 0.54C above that long-term average – within a range of uncertainty from 0.36-0.72C. By contrast the new model, known as HadGEM3, gives a rise about one-fifth lower than that of 0.43C – within a range of 0.28-0.59.
The news has been seized upon by climate sceptics who were already arguing that global warming had “stopped” since the record breaking year of 1998 and that this new development further undermines both climate science itself as well as any policy response to rising temperatures. Climate scientists have responded saying that to draw such a conclusion is misleading.March 9, 2013 at 9:45 am #531442
What the met office says about the data that the met office has collected and presented.
8 January 2013 – There has been media coverage today about our experimental decadal global temperature prediction, which is routinely updated in December each year.
The latest decadal prediction suggests that global temperatures over the next five years are likely to be a little lower than predicted from the previous prediction issued in December 2011.
However, both versions are consistent in predicting that we will continue to see near-record levels of global temperatures in the next few years.
This means temperatures will remain well above the long-term average and we will continue to see temperatures like those which resulted in 2000-2009 being the warmest decade in the instrumental record dating back to 1850.
Decadal predictions are specifically designed to predict fluctuations in the climate system through knowledge of the current climate state and multi-year variability of the oceans.
Small year to year fluctuations such as those that we are seeing in the shorter term five year predictions are expected due to natural variability in the climate system, and have no sustained impact on the long term warming.
In this case, changes in ocean surface temperatures in some parts of the world over the past year are understood to have made a key contribution to the difference between the 2011 and 2012 forecasts, but other factors will also have played a role.
Century-scale projections are less sensitive to natural variability and updates to the 2012 decadal forecast do not necessarily tell us anything about projections of climate change for the coming century.
The 2012 prediction is the first to use the Met Office’s latest experimental decadal prediction system, based on HadGEM3. This includes a comprehensive set of improvements based on the latest scientific understanding.
HadGEM3 has been thoroughly tested and has more accurately reproduced temperature variations over the past few decades, suggesting it shows greater skill than was available from previous decadal forecast systems.
The Met Office routinely shares its research and this is often placed on our website, encouraging openness and transparency with our scientific colleagues and the public alike.March 9, 2013 at 10:16 am #531443
“Global Warming” to be clear, of the human influenced kind, has not stopped, hasn’t seemed to have stopped and there is no scientific evidence that indicates that.
But if a person reads and or quotes garbage like this (headline from news story) and uses that as evidence… “Global warming stopped 16 years ago, reveals Met Office report quietly released… and here is the chart to prove it”, that’s the only place you’ll find confusion, misunderstanding and fud, about “Global Warming”.
So here we go again, same old same old , placing doubt on the science of “Global Warming” without science to back it up.March 9, 2013 at 10:29 am #531444
casalenta, in this topic I’d like to see new information that further informs us “scientifically” about these matters. That of the how, where, why and the effects of “Global Warming” on humans, animals, plants, all life of this planet.March 9, 2013 at 6:46 pm #531445treetopsdreamingMember
I was amazed by a graph from “The Angry Summer” report released by the Climate Commission (and reported on by various Australian media outlets last week). The report discusses 123 weather records that were broken over a 90 day period in Australia in 2012/2013. (For anyone interested, the full report and images can be found at this link: http://www.climatecommission.gov.au/report/the-angry-summer/. (Please note, that the url is an official .gov.au address.)
Key facts (from the report):
The Australian summer over 2012 and 2013 has been defined by extreme weather events across much of the continent, including record-breaking heat, severe bushfires, extreme rainfall and damaging flooding. Extreme heatwaves and catastrophic bushfire conditions during the Angry Summer were made worse by climate change.
All weather, including extreme weather events is influenced by climate change. All extreme weather events are now occurring in a climate system that is warmer and moister than it was 50 years ago. This influences the nature, impact and intensity of extreme weather events.
Australia’s Angry Summer shows that climate change is already adversely affecting Australians. The significant impacts of extreme weather on people, property, communities and the environment highlight the serious consequences of failing to adequately address climate change.
It is highly likely that extreme hot weather will become even more frequent and severe in Australia and around the globe, over the coming decades. The decisions we make this decade will largely determine the severity of climate change and its influence on extreme events for our grandchildren.
It is critical that we are aware of the influence of climate change on many types of extreme weather so that communities, emergency services and governments prepare for the risk of increasingly severe and frequent extreme weather.March 9, 2013 at 11:36 pm #531446
Bullseye post=354356 wrote: casalenta, in this topic I’d like to see new information that further informs us “scientifically” about these matters. That of the how, where, why and the effects of “Global Warming” on humans, animals, plants, all life of this planet.
Bullseye post=354356 wrote:
A “line of best fit” (google if you don’t know what that means)
Please don’t be insulting – I’ve done as much maths as you have, or more. And I know all about line of best fit. Of course you can do that and you make a line that is still going up, because you want a line that is still going up. But the raw data show that the rise has stalled. Look at the graph: http://www.metoffice.gov.uk/hadobs/hadcrut4/diagnostics.html.
It’s actually too early to tell of course, and a line of best fit will show a continuous rise, but it looks like it has stopped going up, and that’s about all you can say at the moment.
I don’t see how your references to bloggers and radio journalists should be accepted as scientific but my reference to the Met office data cannot.
The predicted rise of 0.43 deg C plus or minus 0.15 or 0.16 by 2016 is well within normal fluctuations in global average temperatures, and it is a prediction based on computer modelling that the scientists themselves admit are limited and probably flawed.
Bullseye post=354356 wrote: In this case, changes in ocean surface temperatures in some parts of the world over the past year are understood to have made a key contribution to the difference between the 2011 and 2012 forecasts, but other factors will also have played a role.
Exactly. Even your own arguments admit there are other factors involved. That’s what I’ve been saying all along. It isn’t as simple as ‘add CO2 and the temperature goes up’. And our scientific understanding is constantly evolving.
Bullseye post=354356 wrote: updates to the 2012 decadal forecast do not necessarily tell us anything about projections of climate change for the coming century.
Thanks for confirming my argument.
Bullseye post=354356 wrote: Global Warming” to be clear, of the human influenced kind, has not stopped, hasn’t seemed to have stopped and there is no scientific evidence that indicates that. But if a person reads and or quotes garbage like this (headline from news story) and uses that as evidence…
So, it’s garbage by definition simply because it doesn’t go along with your theory (upon which you select your facts)… Garbage from a blog is okay. Garbage from a radio presenter is okay, but garbage from a news story is not okay? Can you please present your scientific evidence for these conclusions?
Where is your scientific evidence that the global average temperature is increasing? Where? Show me some new scientific data that shows the global average temperature is still increasing (and not just on some line of best fit – I want the raw data that shows it’s still increasing). Where is it?
As far as I can see your evidence is that the Met office is wrong simply because it doesn’t fit with your theory.
PS. I am completely in favour of humans curbing CO2 emissions, and if that’s what your aim is in posting all these global warming threads I’m right with you, but for me it’s because curbing CO2 emissions means adopting more sustainable technologies, and hopefully at some stage reducing population growth.
PPS. I’m also old enough to remember the coming ice age scare of the 1970s, and I’m no more terrified of global warming than I was of global cooling. Some of the scientists running the coming ice age scare campaign are the same people running this scare campaign (eg. George J. Kukla) See, for example http://wattsupwiththat.com/2013/03/01/global-cooling-compilation/, http://www.globalresearch.ca/global-warming-or-the-new-ice-age-fear-of-the-big-freeze/30336, and http://georgewashington2.blogspot.com.au/2009/12/scientists-considered-pouring-soot-over.html. Some people are still convinced it’s another glaciation that’s coming, such as: http://iceagenow.info/. We often just see what we want to see.
PPPS. I know newspapers are garbage but shock jocks on radio and blogs are ok, but you might be interested in this, which is a pretty good article supporting
your arguments (and therefore not garbage) http://www.huffingtonpost.co.uk/david-hone/has-global-warming-stopped_b_2468966.html. And here’s another (just to
save your Googling finger!) http://www.newscientist.com/article/dn23060-has-global-warming-ground-to-a-halt.html.
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