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HUMANS CAUSE CLIMATE CHANGE
Intergovernmental Panel on Climate Change has recently finished its comprehensive study on the physical science basis on climate change and will soon be releasing the report in stages over a 14-month period. This article is a summary of the report for our discussion.
REPORT OVERVIEW
The report indicates, through a comprehensive study of the different physical factors and compositions, that there is
95% certainty that humans are the dominant cause of climate change since the 1950s.
OBSERVATIONS
Widespread changes in the atmosphere are observed across spatial and temporal scales. Strong evidence has emerged that the physical and biogeochemical state of the oceans has changed during the past forty years. Important parts of the cryosphere, in particular the extent and volume of snow and ice, have changed over the latter half of the 20th century. Paleoclimate archives provide quantitative information on the range of naturally driven changes in the climate system on time scales from centuries to millions of years
Atmosphere
Widespread warming is observed from the surface of the Earth throughout the troposphere and cooling is identified in the stratosphere. Globally averaged near surface temperatures have increased since the beginning of the 20th century and the warming has been particularly marked since the 1970s. Each of the last three decades has been significantly warmer than all preceding decades since 1850.
Ocean
Based on independent observational systems and datasets, and their agreement, it is virtually certain that the upper ocean has warmed since 1971, and that ocean warming dominates the change in the global energy content. Largest warming is found near the sea surface (>0.1°C per decade in the upper 75 m), decreasing to about 0.015°C per decade by 700 m, for the time period 1971 to 2010. It is likely
that the deep ocean has warmed below 3000 m depth since the 1990s. The global ocean has warmed at a rate of <0.01°C per decade below 4000 m over this time interval. It is very likely that the Southern Ocean has warmed throughout the full ocean depth since the 1990s, at a rate of about 0.03°C per decade.
Cryosphere
More comprehensive and improved observations strengthen the evidence that the i
ce sheets are losing mass, glaciers are shrinking globally, sea ice cover is reducing in the Arctic, and snow cover is decreasing and permafrost is thawing in the Northern Hemisphere. Ice is being lost from many of the components of the cryosphere, although there are significant regional differences in the rates of loss. There is very high confidence that globally, glaciers continue to shrink and lose mass, but there is less agreement on the rates of mass loss. Recent estimates of global glacier mass loss based on independent methods range from 210 [145 to 275] Gt yr to 371 [321 to 421] Gt yr –1, based on different time windows since 2003.
Sea level
It is unequivocal that global mean sea level is rising as is evident from tide gauge records and satellite data. Over the 20th century the mean rate of increase was between 1.4 to 2.0 mm yr, and between 2.7 and 3.7 mm yr since 1993. It is likely
that rates of increase were similar to the latter between 1930 and 1950
Carbon and other Biogeochemical quantities
More than half of the total carbon emitted by human activities has been taken up by the ocean and the land since 1750. The remainder has caused an increase in the atmospheric CO2 concentration by over 40% since 1750, and by about 10% since 1990.
Paleoclimactic Records
Analyses of a number of independent paleoclimatic archives provide a multi-century perspective of Northern Hemisphere temperature and indicate that 1981–2010 was very likely the warmest 30-year period of the last 800 years.
DRIVERS OF CLIMATE CHANGE
Natural and anthropogenic drivers cause imbalances in the Earth's energy budget. The strongest anthropogenic drivers are changes in greenhouse gas concentrations and aerosols. These can now be quantified in more detail. Globally, CO2 is the strongest driver of climate change compared to other changes in the atmospheric composition, and changes in surface conditions. Its relative contribution has further increased since the 1980s and by far outweighs the contributions from natural drivers. CO2 concentrations and rates of increase are unprecedented in the last 800,000 years and at least 20,000 years, respectively. Other drivers also influence climate on global and particularly regional scales.
Evaluation of Climate Models
Development of climate models has resulted in more realism in the representation of many quantities and aspects of the climate system, including large scale precipita
tion, Arctic sea ice, ocean heat content, extreme events, and the climate effects of stratospheric ozone.
Key Metrics Characterizing Anthropogenic Climate Change
Equilibrium climate sensitivity is likely in the range 2°C–4.5°C, and very likely above 1.5°C. The most likely value is near 3°C. Equilibrium climate sensitivity greater than about 6°C–7°C is very unlikely. The total amount of anthropogenic emissions of long-lived greenhouse gases largely determines the warming in the 21st century. The global mean warming per 1000 PgC is very likely between 0.8°C–3°C.
PROJECTIONS
Projections of changes in the climate system are based on simulations using a hierarchy of climate models ranging from simple climate models, to models of intermediate complexity, and comprehensive Earth System Models. These models simulate changes based on a variety of scenarios of natural and anthropogenic forcings.
Near-Term Projections: Atmosphere
A future volcanic eruption similar in size to the 1991 eruption of Mount Pinatubo would cause a rapid drop in global mean surface air temperature of several tenths of 1°C in the following year, with recovery over the next few years. Possible future reductions in solar irradiance would reduce global mean surface air temperature, but such cooling is
unlikely to exceed –0.1°C by 2050.
Near-Term Projections: Ocean
It is virtually certain that globally-averaged surface and upper ocean (top 700 m) temperatures averaged over 2016–2035 will be warmer than those averaged over 1986–2005.
Near-Term Projections: Cryosphere
It is very likely that there will be continued loss of sea ice extent in the Arctic, decreases of snow cover, and reductions of permafrost at high latitudes of the Northern Hemisphere by 2016–2035. Using RCP4.5, Arctic sea ice area is projected to decr
ease by 28% for September and 6% for February; Northern Hemisphere snow cover area is projected to decrease by 4.0 [2.1 to 5.9] % (one standard deviation) for a March-April average; annual mean near-surface permafrost is projected to decrease by
18%.
Long-Term Projections: Temperature
By mid-21st century, the rate of global warming begins to be more strongly dependent on the scenario. For RCP4.5, 6.0 and 8.5, global mean surface air temperatures are projected to at least likely exceed 2°C warming with respect to preindustrial by 2100, and about as likely as not to be above 2°C warming for RCP2.6.
Long-Term Projections: Water Cycle
Changes in precipitation in a warming world will not be uniform. The high latitudes are very likely to experience larger amounts of precipitation. Many regions in the mid-latitudes that are arid and semi-arid will likely experience less precipitation, while those that are moist will likely receive more precipitation. While there is high confidence
in patterns of these changes, there is only low confidence in the magnitude
Long-Term Projections: Sea Level
It is very likely that the rate of global mean sea level rise during the 21st century will exceed the rate observed during 1971–2010 for all RCP scenarios. Together, ocean thermal expansion and glaciers are very likely to make the largest contributions during the 21st century.
Long-Term Projections: Climate Stabilization, Commitment and Irreversibility
Many aspects of climate change will persist for centuries even if concentrations of greenhouse gases are stabilised. This represents a substantial multi-century commitment created by human activities today. Emission pathways that
likely limit warming below 2°C above pre-industrial by 2100 indicate that CO2 equivalent emissions cannot exceed 8.5–12.6 PgC yr by 2020, and 4.6–6.3 PgC yr by 2050. Continuing greenhouse gas emissions beyond 2100 as in the RCP8.5 extension induces a total radiative forcing above W m by 2300 that leads to a warming of 8.7 [5.0–11.6] °C by 2300 relative to 1986–2005. Substantial sustained reductions of emissions beyond 2100 could keep the total radiative forcing below 2 W m by 2300, as for example in the RCP2.6 extension, which reduces the warming to 0.6 [0.3–1.0] °C by 2300. For scenarios driven by carbon dioxide alone, global average temperature is projected to remain approximately constant for many centuries following a complete cessation of emissions. Thus a large fraction of climate change is largely irreversible
on human time scales, except if net anthropogenic greenhouse gas emissions were strongly negative over a sustained period.
Surface melting of the Greenland ice sheet is projected to exceed accumulation for global mean surface air temperature over 3.1 [1.9–4.6] °C above preindustrial, leading to ongoing decay of the ice sheet. The loss of the Greenland ice sheet is not inevitable,
because surface melting has long time scales and it might re-grow to most of its original volume if global temperatures decline. However, a significant decay of the ice sheet may be irreversible.
Source
Intergovernmental Panel on Climate Change Report
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Pandemona
Charlie Sheens House51449 Posts
Would prefer Humans "Attribute" to Climate Change because that what the report says xD
They said it,s 95% certain Humans have "contributed" to Climate Change with Pollution etc, and that the global sea level will rise by 80cm before the end of the century.
Dominant? I don't think that is the right wording
The latest report from the Intergovernmental Panel On Climate Change (IPCC), delivered in Stockholm, warns that it is now 95% certain that global temperatures are rising and that human activity is to blame.
Is how i see it, that they just contribute. They can't pin point the exact cause of climate change, but they know pollution effects it as well as
The IPCC is under pressure from governments to explain why the rise in global surface temperatures has stalled over the last 15 years. Sceptics argue it is evidence computer models of the climate are wrong. But scientists counter that the planet warms in fits and starts. They point to evidence that an upwelling of cold water in the Pacific Ocean has absorbed heat from the atmosphere - but that is only temporary.
Another quote that needs addressing fast is who is right and what isn't.
This is unwelcome news so people want to shoot the messenger," he said.
"What people tend to do is look at some little piece of the jigsaw and say 'look this demonstrates that it's not real or it's not happening' and then they feel better because they don't have to worry about it.
"But the whole exercise that the IPCC is going through is to look at the whole picture and see the general patterns that emerge. It's the pattern in the reduction of snow and ice and increasing temperature that says there is something odd going on here."
Another point that needs watching closely, the way the Earth flexes in climate has been going on for YEARS. I watched a famous documentary on it from Professor Hawking back a few years ago when he was on about the North and South Pole locations change geometrically which can help contribute to crazy weather patterns and also they predicted that this is the reason for ice ages. The only evidence they have or theory i can't remember the exact wording, is that the polar shift theory is the axis of the earth moves, and over the 200million years they predict it has moved by 55 degrees. Thus this the reason for the random weather events. But it is obviously more complex than just that, but it is also another reason you can throw into the occasion and i prefer to put my eggs into this basket as well as pollution being a problem.
This discussion can go on all day and night with me as i just don't understand how we have came some 150years of using heavy polluting machines/cars etcetc and it is still getting worst and worst? Industrial revolution was just a tiny bit less than the pollution we have produced this year or since the last record of data yet we are saying that is the reason? But what about the 100 years prior to this day why wasn't it getting worst back then? It is very interesting!
Pole Shift Hypothesis
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AUFKLARUNG takes his name serious
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I think it would be interesting to add to the OP how this panel was created. I can't find the article right now, but They studied over 9000 different publications (I think it was 9200), some of them saying that climate change is directly connectd to pollution and some saying the contrary, and used their own tools to get there. I'll try to find the info. ASAP.
It's an incredible report and I still don't understand sceptics after reading through it.
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Climate change has always happened. Do humans speed it up? Probably. But if climate change never happened naturally the Earth would still be a frozen ball of ice.
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On September 27 2013 23:54 Infernal_dream wrote:
Climate change has always happened. Do humans speed it up? Probably. But if climate change never happened naturally the Earth would still be a frozen ball of ice.
The problem with the acceleration caused by humans is that combined with extensive environmental destruction it is putting a huge strain on the ecosystem. The average layman probably does not appreciate how vital biodiversity is to, well everyone.
Still, ignoramuses and people with zero knowledge of the actual facts or even a basic understanding of the science involved will continue to claim that "the science is inconclusive!" and "there is not a scientific consensus!" because the oil companies managed to drum up some third rate huckster that they could pay to sit on talkshows and claim that global warming is not greatly affected by humans.
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How exactly can the deep ocean be warming as a result of human interference when it takes hundreds of years for the ocean current to circulate.
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On September 27 2013 23:54 Infernal_dream wrote:
Climate change has always happened. Do humans speed it up? Probably. But if climate change never happened naturally the Earth would still be a frozen ball of ice.
"climate change" is indeed a bit of a misnomer; the accelerated change in weather patterns, temperatures, sea levels etc. would obviously count as "climate change" but comprise of something far more serious than the normal climate fluctuations that have occurred over the last few million years.
On September 28 2013 00:05 a176 wrote:
How exactly can the deep ocean be warming as a result of human interference when it takes hundreds of years for the ocean current to circulate.
why would ocean current matter if global warming is occurring on a global scale? (and besides, it's the surface temperature that matters since it directly contributes to precipitation / melting of glaciers / etc)
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On September 27 2013 23:44 Douillos wrote:It's an incredible report and I still don't understand sceptics after reading through it.
Intriguingly two of the german main contributors to the panel called themselves sceptics, b/c as they said it is the scientific approach to be skeptical until a hypothesis is proven.
Many of the proponents and profiteers of the climate change media hype try to shift the debate from a facts based "right or wrong" to a moral based "good vs evil", which is extremely questionable in my eyes. A somber climate discussion instead would be nice, but seems far away with an aggressive frenzied Earth cult on one side and paid by Exxon et al scientists on the other.
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No, they don't..
User was banned for this post and fifteen!!! previous mod actions for throwaway shitty one liners like it.
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On September 28 2013 00:09 Sinedd wrote:
No, they don't..
What is this even supposed to mean?
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On September 28 2013 00:12 Squat wrote:What is this even supposed to mean?
obviously cars and big oil and cow farts are the cause, not humans
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On September 28 2013 00:13 synapse wrote:Show nested quote +On September 28 2013 00:12 Squat wrote:On September 28 2013 00:09 Sinedd wrote:
No, they don't.. What is this even supposed to mean? obviously cars and big oil and cow farts are the cause, not humans
Semantics, we meet again!
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On September 28 2013 00:13 synapse wrote:Show nested quote +On September 28 2013 00:12 Squat wrote:On September 28 2013 00:09 Sinedd wrote:
No, they don't.. What is this even supposed to mean? obviously cars and big oil and cow farts are the cause, not humans
You Sir are a true gentleman and scholar for pointing this out. Solution is simple then: Stop driving cars, eating cows and using oil in general. Thank god all this can be done by humans, not cars, cows or oil....
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Edit, forgot to get a science degree before coming here.
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Title is a bit misleading; though you do correct it in the body of the piece itself. Humans are not the sole cause, but humans are exacerbating the situation through polution etc.
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On September 28 2013 00:32 sekritzzz wrote:
I know I'm going against the current here, but climate change advocates should consider giving up. Its a losing battle. Most common people in the world simply don't care. Let alone business men with their factories. People around the world have more pressing issues to care about, like getting food on their table at night.
Climate change is the last thing most people of the world even think of. Even if they all understood it, I doubt they would even care that much in the short term to change their habits. The only semi-serious people about it are Europeans, and to be frank they hardly dent the world population. My take on it is that humans will adapt. If UV rays are burning us, or rising sea levels threaten us, we will adapt. If we don't adapt and die, then that's the world for you. Climate change won't be taken seriously unless the harmful effects are actually hurting people right now, right here. That is just how humans are.
That's the legacy of the being a barely evolved primate a hair's breadth away from a chimp in action.
The important thing in the long run is not necessarily to preserve human life specifically, but at least try to preserve the potential for some advanced form of life on this planet at all.
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It's hard to believe this without thinking the people that come up with "climate change" are a bunch of tin foil hat wearing whack jobs. My mom once told me that the temperature in the house is going up, so what now there is climate change in our house? The temperature went back to normal later. Same thing here, these guys have no way of proving anything and there is no danger so what are they trying to do other than create conspiracies.
User was banned for this post.
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On September 27 2013 23:44 Douillos wrote:
I think it would be interesting to add to the OP how this panel was created. I can't find the article right now, but They studied over 9000 different publications (I think it was 9200), some of them saying that climate change is directly connectd to pollution and some saying the contrary, and used their own tools to get there. I'll try to find the info. ASAP.
It's an incredible report and I still don't understand sceptics after reading through it.
What, over 9000!?!?!?
User was warned for this post
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United States5162 Posts
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EPT
