News Section
Stories from Climate Central's Science Journalists and Content Partners

The Last Time CO2 Was This High, Humans Didn’t Exist

Repost This

The last time there was this much carbon dioxide (CO2) in the Earth's atmosphere, modern humans didn't exist. Megatoothed sharks prowled the oceans, the world's seas were up to 100 feet higher than they are today, and the global average surface temperature was up to 11°F warmer than it is now.

As we near the record for the highest CO2 concentration in human history — 400 parts per million — climate scientists worry about where we were then, and where we're rapidly headed now.

According to data gathered at the Mauna Loa Observatory in Hawaii, the 400 ppm mark may briefly be exceeded this month, when CO2 typically hits a seasonal peak in the Northern Hemisphere, although it is more likely to take a couple more years until it stays above that threshold, according to Ralph Keeling, a researcher at the Scripps Institute of Oceanography.

CO2 levels are far higher now than they have been for anytime during the past 800,000 years.
Click image to enlarge. Credit: Scripps Institution of Oceanography.

Keeling is the son of Charles David Keeling, who began the CO2 observations at Mauna Loa in 1958 and for whom the iconic “Keeling Curve” is named.

Carbon dioxide is the most important long-lived global warming gas, and once it is emitted by burning fossil fuels such as coal and oil, a single CO2 molecule can remain in the atmosphere for hundreds of years. Global CO2 emissions reached a record high of 35.6 billion tonnes in 2012, up 2.6 percent from 2011. Carbon dioxide and other greenhouse gases warm the planet by absorbing the sun’s energy and preventing heat from escaping back into space.

The news that CO2 is near 400 ppm for the first time highlights a question that scientists have been investigating using a variety of methods: when was the last time that CO2 levels were this high, and what was the climate like back then?

There is no single, agreed-upon answer to those questions as studies show a wide date range from between 800,000 to 15 million years ago. The most direct evidence comes from tiny bubbles of ancient air trapped in the vast ice sheets of Antarctica. By drilling for ice cores and analyzing the air bubbles, scientists have found that, at no point during at least the past 800,000 years have atmospheric CO2 levels been as high as they are now.

That means that in the entire history of human civilization, CO2 levels have never been this high.

The Keeling Curve, showing CO2 concentrations increasing to near 400 ppm in 2013. 
Credit: NOAA.

Other research, though, shows that you have to go back much farther in time, well beyond 800,000 years ago, to find an instance where CO2 was sustained at 400 ppm or greater. 

For a 2009 study, published in the journal Science, scientists analyzed shells in deep sea sediments to estimate past CO2 levels, and found that CO2 levels have not been as high as they are now for at least the past 10 to 15 million years, during the Miocene epoch.

“This was a time when global temperatures were substantially warmer than today, and there was very little ice around anywhere on the planet. And so sea level was considerably higher — around 100 feet higher — than it is today,” said Pennsylvania State University climate scientist Michael Mann, in an email conversation. “It is for this reason that some climate scientists, like James Hansen, have argued that even current-day CO2 levels are too high. There is the possibility that we’ve already breached the threshold of truly dangerous human influence on our climate and planet."

Sea levels are increasing today in response to the warming climate, as ice sheets melt and seas expand due to rising temperatures. Scientists are projecting up to 3 feet or more of global sea level rise by 2100, which would put some coastal cities in peril.

While there have been past periods in Earth's history when temperatures were warmer than they are now, the rate of change that is currently taking place is faster than most of the climate shifts that have occurred in the past, and therefore it will likely be more difficult to adapt to. 

A 2011 study in the journal Paleoceanography found that atmospheric CO2 levels may have been comparable to today’s as recently as sometime between 2 and 4.6 million years ago, during the Pliocene epoch, which saw the arrival of Homo habilis, a possible ancestor of modern homo sapiens, and when herds of giant, elephant-like Mastadons roamed North America. Modern human civilization didn’t arrive on the scene until the Holocene Epoch, which began 12,000 years ago.

Regardless of which estimate is correct, it is clear that CO2 levels are now higher than they have ever been in mankind’s history. With global CO2 emissions continuing on an upward trajectory that is likely to put CO2 concentrations above 450 ppm or higher, it is extremely unlikely that the steadily rising shape of the Keeling Curve is going to change anytime soon.

"There's an esthetic to the curve that's beautiful science and troubling reality,” Keeling said. “I'd very much like to see the curve change from going steadily upward to flattening out."

Related Content
CO2 Emissions Expected to Rise Significantly By 2030
Global Carbon Emissions Hit Record High
G
lobal CO2 Levels Set to Pass 400 ppm Milestone
In the Curve: Monitoring Rising Carbon Emissions

Comments

By Eric Peterson (Front Royal, VA 22630)
on May 3rd, 2013

From wikipedia: “The formation of the Isthmus had major consequences on global temperatures, since warm equatorial ocean currents were cut off and an Atlantic cooling cycle began, with cold Arctic and Antarctic waters dropping temperatures in the now-isolated Atlantic Ocean.”  http://en.wikipedia.org/wiki/Pliocene

Geography dictated climate and sea level, not CO2.

Reply to this comment

By Barn Cat (Neenah, WI)
on May 3rd, 2013

Exactly. The last time carbon dioxide was this high the average global temp was 11º warmer. That alone proves that the CO2 level is a meaningless measurement. It was a great industry for awhile though. They managed to use panic, lies, and half truths to generate millions in book sales, speaking fees, and research grants. The only “climate scientists” who are worried are the ones smart enough to wonder how long the public will buy this scam when the earth stopped warming in 1998.

Reply to this comment

By Andrew
on May 3rd, 2013

Nice try, Barn Cat, but no, that is not correct. As Skeptical Science summarizes better than I can:

“Natural climate change in the past proves that climate is sensitive to an energy imbalance. If the planet accumulates heat, global temperatures will go up. Currently, CO2 is imposing an energy imbalance due to the enhanced greenhouse effect. Past climate change actually provides evidence for our climate’s sensitivity to CO2.”

Reply to this comment

By Truth Setsyoufree
on May 3rd, 2013

Good try, but no cigar. Why were polar caps on all the planets in solar system ebbing at the same time ours was? The sun, When the polar regions on our planet grow, so do the ones on the other planets. Again, due to cycles in the sun. So our CO2 cannot and never has been the cause as growth/contraction of polar caps happens on all the planets the same way at the same time. Also, What do plants breathe? CO2 -so when CO2 levels go up what happens on the ground? Plants, trees, and green things thrive. When plants and trees thrive what do they do ? Emit oxygen as the normal byproduct of photsynthesis.
Also, there is more CO2 emitted by one volcano than all the industialization of the earth from the beginning of time.
I do believe we are to be good stewards of the planet and take care of what God created for us.
Climate change hoax and CO2 taxes do nothing but cost average humans money and make greedy ones more. I will have nothing to do with that.
Thank You,
Texas Truth

Reply to this comment

By Bigg-D
on May 3rd, 2013

Hey Truth setsyoufree, how about a little research, eh? Mars ice caps are receding due to sublimation, not ‘melting’. Two completely different processes. Put a tray of ice in your freezer and leave it for 3-4 months and all the ice will be gone. You can’t tell me that that is a result of ‘melting’ because your freezer was never above freezing. If your freezer was above the zero mark, might I suggest a new freezer. And lets completely forget that fact that at least one of Mars ice caps isn’t water. It’s CO2.

But crawl back into your little hermit hole and carry on. Nothing to see here, right?

Reply to this comment

By AMAZON
on May 3rd, 2013

This is PURE NONSENSE article.  I am an Earth Scientist (geology, climatology, meteorology) and this is pure political propaganda.  Please…  stop this.

Reply to this comment

By Mike
on May 3rd, 2013

CO2 is a life-giving gas.  Plants take in CO2 to make Oxygen (O2) by photosynthesis.  The O2 is consumed by humans and animals to produce CO2 as a byproduct.  This life cycle of CO2->O2->CO2… is a cycle of life.  If you increase CO2, you increase O2 meaning more plants, and more animals and humans.  So, a tax on CO2 is a tax on life .  The 1% is sucking the life out of the 99%.  If you are reading this, I am 99% sure you are the 99% smile 

BTW, if CO2 is warming the earth, why is this Spring feel like Winter in most of the Northern Hemisphere.  I remember it was damn hot in Michigan, USA in the 1980’s.  Memorial Day (end of May) was always in the upper 80’s to mid 90’s.  We used to have a tradition to go swimming in the beach.  There’s no way I would do that now as temperatures dropping to the 70’s for the past decade.

Reply to this comment

By Tom Paine (San Francisco, California)
on May 3rd, 2013

All you global warming lunatics should take your eco-religion and leave, but not before we all laugh at you one more time, thank you

Reply to this comment

By Dave (Basking Ridge, NJ 07920)
on May 3rd, 2013

Great article.

Reply to this comment

By JB13
on May 3rd, 2013

So the last time CO2 was this high, the climate was much different than it is now. And this doesn’t cause you to rethink your hypothesis, why…?

Reply to this comment

By Wesley S. (South Hadley, MA 01075)
on May 3rd, 2013

“That means that in the entire history of human civilization, CO2 levels have never been this high.” — Yet, it snows in Kansas City in early May.

Reply to this comment

By Leonard Tachner (Irvine, Ca. 92614)
on May 3rd, 2013

“climate scientists worry about where we were then, and where we’re rapidly headed now” . Not so rapidly. It was cool in the first two decades of the 20th century, and cool again from 1940 to 1977. It hasn’t warmed for the past 17 years either. All while the CO2 levels have steadily increased we’ve had more non-warming years than warming years. Now solar activity scientists in Russia are warning that we are likely to start a new mini-iceage that could last hundreds of years.  Given that set of facts, what climate scientists worry even more about is losing their grant money for advocating a hypothesis that’s quickly losing steam and credibility.

Reply to this comment

By Rik Blumenthal (Auburn)
on May 3rd, 2013

Bigg-D CO2 does not have a liquid phase under atmospheric conditions here or on Mars, in fact it does not form a liquid phase below a pressure of 5.1 atmospheres.  For such a substance, sublimation is the equivalent of melting.  May I recommend you take a freshman-level chemistry course before you put your foot in your mouth again.

Reply to this comment

By John Ward (Gainesville FL 32605)
on May 3rd, 2013

Eric: The isthmus shuffled global temperatures around; it was not responsible for the overall temperature of the planet. Falling CO2 rates during this period allowed more heat to escape, which lowered the temperature.

Barn cat:  “The last time carbon dioxide was this high the average global temp was 11º warmer. That alone proves that the CO2 level is a meaningless measurement.” Not at all. It takes a while to heat things up, possibly centuries.

Truth Setsyoufree: “Why were polar caps on all the planets in solar system ebbing at the same time ours was?” Where is your evidence that they were?

You are passing on misinformation: “[ W]hen CO2 levels go up what happens on the ground? Plants, trees, and green things thrive.”  In fact, more Carbon Dioxide in the atmosphere is not necessarily good for plants. http://www.skepticalscience.com/co2-plant-food.htm
More misinformation:“Also, there is more CO2 emitted by one volcano than all the industialization of the earth from the beginning of time.” No: Humans emit 100 times more CO2 than volcanoes. http://www.skepticalscience.com/volcanoes-and-global-warming-intermediate.htm

AMAZON: ” I am an Earth Scientist.” Oh? Have you any publications in peer-reviewed journals? Are you currently doing research? Is there any reason we should believe you rather than the climate scientists who do research and publish, who say, with near-unanimity that we have a serious problem that is only going to get worse if we don’t shut down greenhouse gas emissions and produce the evidence to back their claims?

Mike: “CO2 is a life-giving gas.” See the link I gave Truthsetsyoufree.
“BTW if CO2 is warming the earth, why is this Spring feel like Winter in most of the Northern Hemisphere.” Read this: http://www.climatecentral.org/news/arctic-warming-is-altering-weather-patterns-study-shows

Wesley S.:  See the article I linked Mike to.

The feeble objections made by the above discussants, picked up from denier blogs, unsupported by evidence, and disproved many time over, demonstrate once again how little cause there is to deny the mountain of research warning us of the worsening condition of the planet. Do you folks actually read the articles posted in the website? It’s hare to see how that is possible.

Andrew and Bigg-D: Thanks for some thoughtful observations. We will need more concerned people involved to have any chance of hanging on to a world something like the one we have known.

Reply to this comment

By Tom Ferrell (Saint Hlelena, CA)
on May 3rd, 2013

The great majority of our planet’s CO2 is dissolved in the oceans.  The amount that can be dissolved is inversely proportional to temperature. When ocean temperatures rise, so does atmospheric carbon dioxide as it is released by the warmer water. So remember in “Inconvenient Truth” when Al Gore stood in front of that big chart that showed the historical record from ice cores , the temperature and CO2 graphs tracked closely to each other. Gore implied that was proof of CO2’s role in historical warming. What he didn’t point out (something he and his advisors knew) was that the ice cores had shown the warming came first, and the atmospheric CO2 followed the warming. Climate science isn’t all BS, but there are too many alarmists who mislead for attention, power, or personal gain.

Reply to this comment

By Steve O (Arlington VA 22205)
on May 3rd, 2013

@Truth
(Quote) “Also, there is more CO2 emitted by one volcano than all the industialization (sic) of the earth from the beginning of time. “

Do you just make this stuff up?  Did you actually check to see if there was a shred of truth to your statement before spouting it off?  ‘Cause there’s not.

From http://volcanoes.usgs.gov/hazards/gas/climate.php
“The 35+-gigatons of annual anthropogenic CO2 emissions is about 80 to 270 times larger than the respective maximum and minimum annual global volcanic CO2 emission estimates.”

Also, scientists can determine the source of CO2 in the atmosphere.  That which comes from burning fossil fuels is different from that which comes from volcanoes or from biological sources.  The excess CO2 (that above pre-industrial 280 ppm or so) has come from fossil fuel burning.

I recommend Skeptical Science for understanding the science of climate change.  If you take a look there first, you can save yourself the embarrassment of making completely absurd statements.

 

Reply to this comment

By Joshua Hayes (Indianapolis, Indiana 55555)
on May 3rd, 2013

An ‘Earth Scientist’ named Amazon who doesn’t understand the first thing about global warming. I’m convinced!

Reply to this comment

By Nate (New Berlin, WI 53151)
on May 3rd, 2013

‘The last time there was this much carbon dioxide (CO2) in the Earth’s atmosphere, modern humans didn’t exist. ‘

Obviously, it wasn’t caused by ‘anthropogenic global warming’, so…what’s the excuse for it?

Reply to this comment

By john smith ( )
on May 3rd, 2013

how can ANYBODY with any brain look at data going back 800,000,000 yrs. and watch off chart greenhouse gases from our emissions and post half the uneducated ‘not happening and I dont care what anything says’ bs denialist regurgitations above?

do you have ANOTHER chart which refutes this widely accepted one???

if not WHAT are you basing your extremely ignO8rant denialism on??????  anything at all???? 

if you want to have a GROWN UP discussion post any actual science refuting above ALARMING data?

because it is alarmed you SHOULD be concerned, not say uh uh not happening.

that is childish and very very sc&**ry to contemplate that you are considered a ‘reasoning’ adult or at least old enough to post on a scientific site!!!!!!

if you are worried then DO SOMETHING. pretending something isn’t happening at all, when evidence is rapidly mounting and INDISPUTABLE.  at some point 99.99% certainty from conservative minded scientists has to get people off their a89es and somehow will folks to do SOMETHING!!!!!!

for every record cold somewhere due to extreme out of control climate we have created for ourselves due to greed and shortsightedness, there is record drought in NZ at same time as record flood in argentina as same time as earliest ever wildf!re ‘season’ in CA and extremely unusual may blizzard all AT THE SAME TIME.

GROW up and connect dots for YOUR OWN STABLE CLIMATE! 

you aren’t a denialist island immune from what you are causing! 

your kids whether you are trying to drown out reality WON’T THANK YOU for sh!tINg on them and their generation!

Reply to this comment

By Tom (Gross Pointe, MI 48224)
on May 3rd, 2013

Clueless Deniers seem to think that since the world has not warmed up *yet* to 11°F warmer than it is now from ~ 400 ppm CO2 in the atmosphere, that means thousands of climate scientists don’t know what they are doing.  There is a time lag - climate scientists have been very clear about this “warming in the pipeline”.

The measured radiation imbalance in the TOA (Top of Atmosphere) shows that the new atmosphere composition is causing a radiative forcing of the climate, just as all the climate models show.  The excess heat trapped in the troposphere layer goes mainly (over 90%) into heating the ocean - and the warming ocean is causing the Arctic sea ice to whither away in the summer.  Last year was another big record, smashing the 2007 record.  The oceans, and land, and ice will continue to warm.  Glaciers are melting, the Arctic sea ice will vanish in the summers, the oceans will continue to warm, even the abyss, and will continue to do so until the increased energy radiated from the higher temperature troposphere balances out with the incoming energy from the Sun.  Hence the “pipeline” - until the input/output is balanced, the Earth will continue warming towards it’s new equilibrium point.

2010 was the hottest year on record - and it will continue to get hotter and hotter.  Reality doesn’t care how stupid some humans are.

Reply to this comment

By Craig (LF MN 56345)
on May 30th, 2014

If the Climate is changing and it is because of CO2 then what do we do about? The US has lowered is co2 emissions and does so yearly. Where as China keeps kicking out more CO2 every year. So yell at China or India or any other part of the developing world and tell them they need to stop it. Let’s see how far you get with that.

Reply to this comment

By Paul Bell (San Diego)
on May 3rd, 2013

I love the climate crisis goofballs.  Skeptics believe one thing.  Climate changes over time.  Gets warmer, gets colder.  Mechanism that drives this is poorly understood.

Alarmists have a whole chain of arguments.
Current climate (or perhaps 70’s or 80’s climate) represents perfection and ideal.
Any deviation from this climate will lead to apocalypse
Mankind is causing deviation from the climate utopia of the past.
A gaggle of bureaucrats mandating global energy production policies is the only thing that will save us from doom.

What sounds more reasonable?

Reply to this comment

By Yankee Doodle (Baker, MT 59313)
on May 3rd, 2013

Well, if we want a decrease, raise the legal driving age to 18, then a state by state basis, add a fee to your registration. Enough to make owning a vehicle a true luxury. China is doing it to curb their pollution issue.

Reply to this comment

By what_I_see
on May 3rd, 2013

People do relieze is in history that when carbon dioxide levels rise plant growth rise. Meaning Carbon turning to oxygen simply biology takes care of its self, but the difference from those times and now is that we have cut and remove lots of the plants, and only now does at least the US that I know of tries to replant and regrow the amount of plants that there once was. I am sure there is other countries doing the same, but we are not at the levels of vegetation we need to counter it.

Reply to this comment

By An actual scientist (tx)
on May 3rd, 2013

So funny to see all these rubes try and talk themselves out of believing science. Every legitimate PhD climatologist has known about climate change for decades. Any one who thinks climate science is a hoax does not understand how science works, stop talking about things you don’t understand. Go back to your turnip trucks and leave the science to the scientists!

Reply to this comment

By Coperinicus Maximus (Lagos, Nigeria)
on May 3rd, 2013

You REALLY don’t know what you are talking about, do you?

HINT:  Find a new line of work.  McDonald’s is hiring burger flippers.

Reply to this comment

By Dan Chrisco (Lake City, MI 49651)
on May 3rd, 2013

Ok, there seems to be a lot of banter about this but here are a few things to think about. First, there is a natural balance to the ecosystem (in this case, earth). When there is more CO2 in the atmosphere than can be naturally removed through systematic processes there is a buildup. With massive amounts of glacial and polar ice melting it is only increasing the problem since the ice also trapped untold amounts of CO2 which is added to the atmosphere through evaporation. Second, the Earth’s natural atmospheric cleansing process deposits CO2 along with other substances from the air through precipitation and wind shifts. This process is over the limit of its abilities and results in unpredictable weather patterns as the atmosphere retains all of the extra heat from the over abundance of CO2. Third, the high amount of energy that is trapped in the atmosphere cases more violent weather patterns with high instances of frequency or lack there of depending on the heat balance at a given location. Lastly, for those of you who find it easy to throw stones at those who know what they are talking about because you “believe” you “know” what is really going on should take a few classes or at least visit the local library to learn what you are reading when it comes to this topic. Should you actually become interested in learning more about this situation and how it will continue to overwhelm the natural climate process then I highly suggest reading a few books on atmospheric dynamics, thermodynamics, chemistry, and physics since that will get you to a good working base on knowledge to understand that our biosphere is in serious trouble and getting worse.

Reply to this comment

By NIle
on May 3rd, 2013

Yeah the plant take in CO2 and Emits Oxygen. Stupids, don’t argue that the more CO2 we have the more plant will thrive.  Can’t you see how much deforestation humans have cause and how much CO2 is emitted every year. The amount of CO2 a plant can intake is way less than the amount we are emitting. SO the CO2 is accumulating in the atmosphere and creating dis-balance in the environment.

Reply to this comment

By Mr Green Thumb (Sacramento CA 95833)
on March 29th, 2014

I’m not an expert like everyone here on climatology. I’m here to learn and listen to all of you. Very interesting arguments. But I do know a great deal about plant science. Plants can use way more than 400ppm of CO2. 800 -1500 ppm is very usable by most plant species. Those numbers will make most plants flourish.

Reply to this comment

By Scott Brassfield (Colorado Springs)
on May 4th, 2013

Andrew, thanks for the great article and please hang in their despite denialist garbage.  They doom our grandchildren.  Only in North America are they common.  Latin America and Asia, although poorer, have lower frequencies of climate change denialism.  Are the denialists seen in your responses paid?  Are they just idiots?  They are reminiscent of the lung cancer and tobacco denialists of the 1950’s. Charles Koch, HIMSELF,  funded the BEST, Berkeley Earth Surface Temperature,  study.  Richard Muller, it’s principal scientist and a UC Berkeley physicist and reformed climate change skeptic, after a study of millions of earth surface temperatures, concluded that earth has heated 2.5 degrees F. since 1750.  Warmed 1.5 degrees since 1950.  And he concluded that 74 percent of that warming is extremely likely to be human caused.  And all of it highly likely to be human caused: anthropogenetic.http://thinkprogress.org/climate/2013/01/20/1474571/koch-funded-study-finds-25f-warming-of-land-since-1750-is-manmade-solar-forcing-does-not-appear-to-contribute/ 

I am trying to find the best approach to educating and motivating change.  Facts alone don’t swing opinion away from denialist lies.  Deniers are pseudoscientific but their pseudofacts sound convincing to the general public.  Do we need more TV advertisement to counter the Koch and Exxon sponsored BS?  Do we need Evangelicals with scientific truth, e.g. Katherine Hayhoe, a true climate scientist (referred to by Rush Limbaugh as a ” Christian, climate chick”},  better funded and spreading the gospel of saving creation in churches?

Reply to this comment

By Ann Coulter's Adams Apple (Little Rock, AR.)
on May 4th, 2013

Wow! Just look at all the fact free sock puppet responses, my favorite being Texas Truth!  Sorry but the words Texas and Truth are mutually exclusive terms. This is the same state that gave us George W. Bush. The comments on this site should be limited to people exhibiting some sort of scientific background. CO2 traps heat. CO2 can be deadly. If you don’t believe it then I suggest you place a plastic bag over your head, secure it tightly at the bottom and continue to breathe normally.

Reply to this comment

By Floyd (Ann Arbor, Michigan)
on May 4th, 2013

Wow. The amount of miscomprehension in these comments is staggering.

First, the CO2 <-> O2 cycle is certainly true. However, plant growth is not keeping pace with the increase in available CO2. Quite the opposite: human development means that there are fewer plants to process the CO2. The fact that atmospheric CO2 is going up (which no one denies) means it is not being sequestered. Pretty simple stuff.

Second, despite frantic uninformed claims to the contrary, no scientists are getting rich fleecing the public with panic science. Scientists are by their nature skeptical, and a surefire way to succeed in science is to disprove an existing hypothesis. Indeed, is a scientist were to disprove climate change or evolution or relativity, they would be the most famous scientist in the world. Publishing false claims is simply not tolerated in science. Such instances (and there have been a few in the history of science) are invariably discovered, and the guilty party without fail is booted out of science, with zero possibility of receiving future funding.

I am a computational biologist, so I do not get any grant money even indirectly related to climate change. But having reviewed the literature, I can tell you that this is solid science, and this is the consensus of all biologists. Why is it that so many of you are fervently against the idea of climate change, when it is clear that you have not read any of the relevant research? Same thing with evolution. If you do not understand the science, you cannot claim it to be false. Arguments from personal experience (“I remember it used to be hotter”) is barely relevant; it certainly seems that the sun goes around the Earth, doesn’t it?

Reply to this comment

By John Ward (Gainesville FL 32605)
on May 4th, 2013

Mike, You ask “Why were polar caps on all the planets in solar system ebbing at the same time ours was?” What caps, Mike? “Caps” suggests that all of the solar system planets have frozen caps that are melting along with ours, but Mercury and Venus don’t have “caps,” and we don’t know enough about most of the planets’ atmospheres to determine the causes of changes in them other than getting nearer or farther from the sun, which they do at different times because of orbits of different shape and size than earth’s, and are not the cause of our Arctic warming and, in particular, of its acceleration. Read this:
http://solarsystem.nasa.gov/yss/display.cfm?ThemeID=34&Tab=Background  
and this:
http://www.skepticalscience.com/global-warming-on-mars-intermediate.htm

You also write, “We used to have a tradition to go swimming in the beach.  There’s no way I would do that now as temperatures dropping to the 70’s for the past decade,” and suggest that this means global warming doesn’t exist. One consequence of climate disruption is the creation of regional areas of greater than normal heat and areas of greater cold (although most of the records set are on the heat side), as well as both increased wetness and increased aridness. You cannot draw any conclusions about global warming from regional temperatures. Two of the most comprehensive studies ever done on historical temperatures show that present temperatures are the highest in nearly 1400 years and by the end of the century, if we don’t cut off human-caused greenhouse gas emissions, will be higher than at any since civilization first became possible.
See this:
http://thinkprogress.org/climate/2013/04/23/1903001/the-hockey-stick-lives-new-study-confirms-unprecedented-recent-warming-reverses-2000-years-of-cooling/

In fact, global warming is accelerating:
http://www.skepticalscience.com/new-research-confirms-global-warming-has-accelerated.html

Reply to this comment

By Pete (Durham, NC)
on May 4th, 2013

Climate change deniers, I wish you would actually study the subject, the physics behind greenhouse gases, the way climate works. Without studying the subject, getting a degree in it, working in research, how on Earth do you think you are in any place to challenge the data produced by those that have? The way to change the science is to go out yourselves, become scientists and actually research it. Instead you’re all sat there reading your little conspiracy websites. The day you all start producing the evidence that shows climate change to be wrong, we will take you seriously.

Reply to this comment

By John Crofford (Fitchburg/WI/53713)
on May 5th, 2013

I have a link for those of you who have questions about long-term trends in world temperatures since the start of the industrial revolution:

http://www.noaanews.noaa.gov/stories2010/images/may_62010.gif

Reply to this comment

By David Eccles
on May 5th, 2013

There is no doubt that atmospheric CO2 concentration has risen to values not seen in the last several million years, or that this phenomenon is anthropogenic in origin.

I take issue with the assertion that CO2 has a long life time in the atmosphere. The Mauna Loa records show that there is annual change in CO2 values, with a fall slightly less than the rise. This implies that there is, in fact, a rapid turnover of carbon dioxide, which is the major nutrient required by green plants.

Despite this, most climate scientists appear to have accepted that the rising CO2 values are the principal driver of climate change (even though recent records suggest that the rate of change has fallen while CO2 continues to rise). This assumption may be unwarranted - itsacceptance as the ‘obvious’ driver seems to have diverted attention from other anthropogenic potential drivers such as deforestation and subsequent (not necessarily consequential) desertification, which may have reduced the consumption of carbon dioxide.

The assertion that human fostering of methane-producing livestock also contributes to climate change may also be erroneous. Cattle numbers have certainly increased in Africa, Europe and North America, but before they were domesticated there were enormous herds of native ruminanta such as wildebeest, buffaloes and bison. Perhaps we should praise Cody for getting rid of so many of these.

Rising sea level is another factor for which I find it difficult to blame humanity. The current rate of rise is, in fact, less than the rate of rise at some periods in the last 18,000 years. Many believe that a continuing rise will swamp low-lying atolls but Charles Darwin, over 150 years ago, showed how these were formed by rising sea levels.

We should certainly not be complacent about climate change, but our strategy should be to adapt to it rather than attempt to control it by addresing a single factor that we believe MAY contribute to it.

The greatest problem we face is not climate change, but the depletion of resources by an ever-increasing population. If this leads to warfare it could destroy modern industrial economies, which would probably NEVER recover because all the readily accessible resourcces have already disappeared and the remaining ones require sophisticated means of recovery. Even if humanity survived it couldnever again rise above a mediaeval standard of living and technology

Reply to this comment

By mk
on July 6th, 2014

“I take issue with the assertion that CO2 has a long life time in the atmosphere.”

So much the worse for you.

“The Mauna Loa records show that there is annual change in CO2 values, with a fall slightly less than the rise. This implies that there is, in fact, a rapid turnover of carbon dioxide”

Uh, no, it obviously does no such thing.

Reply to this comment

By Hello there, it's hell out here
on May 5th, 2013

For all of you, religiously denying facts about the earth warming, here it is:

‘GENEVA, 2 May 2013 (WMO) The World Meteorological Organization’s Statement on the Status of the Global Climate says that 2012 joined the ten previous years as one of the warmest — at ninth place — on record despite the cooling influence of a La Niña episode early in the year.’

http://www.wmo.int/pages/mediacentre/press_releases/pr_972_en.html

 

Reply to this comment

By Jackie (Victoria, BC, V8N 3B8)
on May 5th, 2013

How could anyone look at the first graph and believe that the consequences of a huge, rapid change like this will not be devastatingly huge and rapid? (definition of rapid=one century, possibly decades) It is very difficult for me to believe that we can avoid consequences at this point. Wanting to believe we will get out of this unscathed won’t make it so.

Reply to this comment

By Jan Moore
on May 5th, 2013

Wow, the denier plants are really expanding their online territory.

Reply to this comment

By JanMoore
on May 5th, 2013

http://www.youtube.com/watch?v=hWJeqgG3Tl8

The temp leads carbon crock.

Reply to this comment

By Robert Richter (Newtown Square, Pa.19073)
on May 5th, 2013

Venus is our sister planet, similar to Earth in size. It is the hottest of the planets, with a surface temperature of more then 880 degrees Fahrenheit. It is closer to the Sun (67 million miles) than the Earth (93 million miles), but that distance does not account for the very high temperature. Mercury is about 800 degrees also (on the side facing the Sun), but it is much closer to the Sun (35 million miles). The very high temperature on Venus results from a greenhouse effect caused by an atmosphere of mostly carbon dioxide. And this is so despite the fact that much of the Sun’s radiation is reflected away by Venus’s immense cloud cover.

Reply to this comment

By Frunobulax718 (NY, NY 10021)
on May 6th, 2013

“For a 2009 study, published in the journal Science, scientists analyzed shells in deep sea sediments to estimate past CO2 levels, and found that CO2 levels have not been as high as they are now for at least the past 10 to 15 million years, during the Miocene epoch.”

A binary asteroid impact event from around 14.5 million years ago in south-central Germany may have kicked up quite a bit of carbon. There was a large quantity of graphite at the impact site and some of it was even compacted into micro-diamonds. One of the craters was 15 miles in diameter, so this wasn’t a tiny event.

http://en.wikipedia.org/wiki/Nördlinger_Ries

Reply to this comment

By zarith (30308)
on May 6th, 2013

Climate Science, the “science” where being 11 degrees off proves you’re actually right about everything.

I am just thankful you guys didn’t go into structural engineering.

Reply to this comment

By Eric Peterson (Front Royal, VA 22630)
on May 6th, 2013

John Ward (Gainesville FL 32605) said “Eric: The isthmus shuffled global temperatures around; it was not responsible for the overall temperature of the planet. “

Sorry, that is completely wrong: see http://homepages.see.leeds.ac.uk/~earamh/Files/PAGES_Pliocene/Key references/Luntetal2008.pdf for example

Reply to this comment

By R A Chase (Pfafftown NC 27040)
on May 8th, 2013

@John Ward: You need to find a better basis for your comments regarding atmospheric CO2 levels and plant growth response. It is well proven (scientifically, no less) that increasing CO2 (at least up to the point, of course, that it becomes lethal) is a positive factor for growth of most plant species. The UN Climate Change assessment recognizes this fact by forecasting increased crop yields as a positive factor for rising atmospheric CO2 levels. A number of published scientific articles provide similar information. (I have a degree in Plant Science, by the way…)

Reply to this comment

By John Ward (Gainesville, FL 32605)
on May 8th, 2013

Eric, Thanks for the link. The study does indeed conclude that “the closure of the Panama Seaway
during the Pliocene likely increased the rate of, or accelerated the initiation of, NHG [Northern Hemisphere Glaciation].” But they also admit that “it was not a primary factor. A more likely candidate is decreasing levels of pCO2 [ the pressure the CO2 would exert if all other gases were removed] during the Neogene, coupled with fluctuating orbital configurations, culminating in the crossing of a critical threshold” (conclusions, p. 16). In other words, the authors of the study accept the established causes of the glaciation as the dominant ones. For anyone not familiar with them, this video provides a clear explanation: http://www.youtube.com/watch?v=8nrvrkVBt24

Reply to this comment

By Eric Peterson (Front Royal, VA 22630)
on May 9th, 2013

John, thanks for following up.  As we both know, CO2 is an amplifier of climate change by other forcings (the current manmade is one of a few exceptions).  In the case of glaciation, a relatively small forcing from lower obliquity (cooler summers only) can lead to much larger forcing from increased albedo, then lower CO2, then lower temperature to achieve an ice age.  This paper simply points out that the closure may have done the same thing as lower obliquity.  The critical threshold depends mostly on albedo feedback.  That is what is consistent with established Milankovitch theory.

Reply to this comment

By Brian Macker
on June 4th, 2013

The Last Time CO2 Was This High, Humans Didn’t Exist But Plenty of Other Animals Did

Reply to this comment

By Michael Peterson (eastover/sc/29044)
on June 18th, 2013

I am an earth scientist, planetary scientist, genius, astrophyicisit, brain surgeon and I refute everything. And I love citizen science it’s just all so democratic and gives one the freedom to speak what little of their mind they have. Sorry I don’t know any big words my sophistry is just not up to snuff.BTW cigarettes are purfectly safe. Thank you for your attention.

Reply to this comment

By Gary Vasey (Houston, TX)
on June 26th, 2013

I’m also an Earth Scientist with a PhD in paleoclimate. This is political propaganda - wake up and ignore this BS. CO2 in the atmosphere is a function of atmospheric temps - not the other way around.

Reply to this comment

By M. Campbell (Toronto, Ontario Canada )
on August 6th, 2013

And according to a study I am conducting I have proven conclusively that open umbrellas cause rain. Every day that it is raining I see an abundance of open umbrellas yet on sunny days hardly any. Same logic. How come the CO2 levels have been rising for the last 10 years but the global temperatures are falling. Why the record ice level increase in Antarctica?
Can I get a job on your research team and how much does it pay?

Reply to this comment

By mk
on July 6th, 2014

” And according to a study I am conducting I have proven conclusively that open umbrellas cause rain. Every day that it is raining I see an abundance of open umbrellas yet on sunny days hardly any. Same logic. “

No, it’s YOUR logic. The actual logic of global warming is apparently beyond your comprehension.

“How come the CO2 levels have been rising for the last 10 years but the global temperatures are falling.”

Because it’s not true.

“Why the record ice level increase in Antarctica?”

Again, not true ... there has been a small increase in SEA ice, but the CONTINENT is draining and breaking away.

And so it goes with denier claims ... THEY’RE FALSE.

Reply to this comment

By Mary Oneil (chicago, IL, 60614)
on August 8th, 2013

Scientists have known about global warming for decades. It’s real. So let’s move on to what we can do about it. http://clmtr.lt/cb/vvh0bM6

Reply to this comment

By John (Swindon Wilts SN5 5SQ)
on October 1st, 2013

All this cyber-blather will have raised the CO2 levels up a bit, that’s for sure. Pity you people weren’t paying the energy bills we have in Britain to subsidise useless wind turbines. But then over here the lunatics are running the asylum.

Reply to this comment

By Brett Crook (wattle grove / W.A./ 6107/ australia)
on April 8th, 2014

For a different, positive take on solutions to this whole problem, check out the work and ideas of Alan Savory on TED Talks. Win win on all levels, global / local, economic / social / political. I can only see radical vegetarians having a problem with this one=) . If we don’t stop desertification anything else becomes academic.

Reply to this comment

By Carl panzarella (New caney Texas)
on May 17th, 2014

Climate please help me with this. If all of the fossil fuels that are in the earth and calcium carbonate were once living organisms, before that they must have been carbon dioxide. What was the carbon dioxide content of the atmosphere and the temperature of the earth.  It seems that if we extrapolate from current hypotheses the temperature wound have been too hot to support life as we know it

Reply to this comment

By mk
on July 6th, 2014

”  It seems that if we extrapolate from current hypotheses the temperature wound have been too hot to support life as we know it”

HUMAN life, but not life in general.

Reply to this comment

By Ralph Gardner (Cleveland/Ohio/44103)
on May 18th, 2014

Hasn’t it been warming since the Little Ice Age and wasn’t there farming in Greenland before this? Do the CO2 levels reflect this?

We need to replace fossil fuel anyway so money spent on developing alternate sources of energy isn’t wasted and it is already providing cheaper energy in some cases,

Reply to this comment

By Brian (Dallas,PA 18612)
on May 24th, 2014

Water vapor is the biggest greenhouse gas not CO2 or methane.

Reply to this comment

By Mike (Oceanside Ca)
on June 6th, 2014

I read a lot of stuff about c 02 and how bad it is for the earth. We are told that if we don’t curtail c 02 emissions, we are doomed. What I would like to know is how much of a reduction is needed and what effect it will have and when.
If the global warmests are right and we reduce our carbon output on a global scale and the temperature decreases, what happens if we cool the earth too much?

Reply to this comment

Name (required):
Email (required):
City/State/Zip:
Enter the word "climate" in the box below:

[+] View our comment guidelines.

Please note: Comment moderation is enabled. Your comment will not appear until reviewed by Climate Central staff. Thank you for your patience.