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Statistically, humanity is almost certainly responsible for global warming

By Chris Wood
January 26, 2016
Statistically, humanity is almost certainly responsible for global warming
A new study has estimated the likelihood of humanity's actions being responsible for current warming trends, and the results are damning
A new study has estimated the likelihood of humanity's actions being responsible for current warming trends, and the results are damning
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A new study has estimated the likelihood of humanity's actions being responsible for current warming trends, and the results are damning
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A new study has estimated the likelihood of humanity's actions being responsible for current warming trends, and the results are damning

The world is getting warmer, with 13out of the 15 warmest years on record occurring in the currentcentury. But just how sure are we that humanity's burning of oil andcoal is the key factor in the temperature increase? A new project,led by researchers at the Potsdam Institute for Climate ImpactResearch, has answered that very question, working to estimate the likelihood of those temperature trends occurringnaturally.

That likelihood has been estimated tobe incredible tiny in the past, as low as 1 in 650 million. Theproblem is that natural climate change – warming that would occurwithout the presence of mankind – tends to gradually rise and fallover periods of at least several years at a time. That gradualprocess makes it difficult to accurately separate the natural andhuman causes of warming, in turn making it tough to arrive at a trulyreliable estimate.

To improve our understanding, thePotsdam Institute team used temperature data ranging from 1880 to2014 to map the recorded fluctuations, while using computersimulations of the planet's climate to take the natural warmingfactor into account. Once all the numbers were crunched, the teamfound the likelihood of the trend occurring naturally to be between 1in 5,000 and 1 in 170,000.

While those numbers are significantlyhigher than some other estimates, the researchers believe that theodds are low enough to suggest that the observed temperatures areextremely unlikely to occur without the impact of humanity'sgreenhouse gas emissions. In fact, the stats suggest that the recordtemperatures are roughly 600 to 130,000 times more likely to haveoccurred as a result of human emissions than without them.

Furthermore, while the data used forthe analysis only runs up until 2014, the temperature readings for2015, which arrived after the work was complete, show it to be thewarmest year on record. Had that data been included in the study,then the numbers would have been more damning, with the chance ofhumanity's actions not being the cause shrinking even further.

"Natural climate variations justcan't explain the observed recent global heat records, but man-madeglobal warming can," said study co-author Stefan Rahmstorf,summarizing the findings. "It has led to unprecedented local heatwaves across the world – sadly resulting in loss of life andaggravating droughts and wildfires. The risk of heat extremes hasbeen multiplied due to our interference with the Earth system, as ouranalysis shows."

The researchers published the findingsof their study in the journal Scientific Reports.

Source: Potsdam Institute for Climate Impact Research

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EnvironmentClimate CrisisGreenhouse Gas Emissions
38 comments
Chris Wood
Chris specializes in science and consumer technology for New Atlas, but also likes to dabble in the latest gaming gadgets. He has a degree in Politics and Ancient History from the University of Exeter, and lives in Gloucestershire, UK. In his spare time you might find him playing music, following a variety of sports or binge watching Game of Thrones.

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38 comments
Doubting_Thomas
1. The Earth is 4.5 billion years old. https://en.wikipedia.org/wiki/Age_of_the_Earth The 150 year trend data used in this study = .000003% of the earth’s life. If you were a scientist tasked with determining weather trends for a given year and you based your calculations on a 1 second snapshot of weather data, people would likely challenge your conclusions because clearly 1 second of data cannot be a representative statistical sample for an entire year. Yet it is the very same ratio as above - .000003%.
2. Human Carbon sources represent 5% of all sources according to the Intergovernmental Panel on Climate Change. Although human sources must have some impact, it is difficult to believe that the 5% human contribution has a greater impact that the 95% contribution from natural sources.
3. Carbon Dioxide comprises .04% of the Earth’s atmosphere. Based on what we read in the mainstream press, the vast majority of scientists around the world believe this is what is driving global warming. Oddly, the atmosphere on Mars is 95.32% carbon dioxide. Yet Mars has no greenhouse effect. The temperature of Mars ranges from plus 20 - 40 F during the day to minus 400 F during the night. Is carbon dioxide truly the lever?
4. The Society of Civil Engineers rates the US infrastructure as a D+ and estimates that $3.6B of work is required to bring things back to good condition. http://www.infrastructurereportcard.org Before we burden our children with billions of dollars in carbon sequestering projects at the expense of aging bridges and water supplies, shouldn’t we have a better understanding of the underlying science?
D[]
Doubting_Thomas brings up a couple of good points. These data are based on a relatively small snapshot.
It is interesting to read this article and see that the authors admit that it is "difficult to accurately separate the natural and human causes of warming, in turn making it tough to arrive at a truly reliable estimate." However if you use any social media news sources then: "Climate Warming Data is UNDENIABLE!!!". Peer-reviewed work and commentary by scientists on research findings comment on the lack of hard-evidence on a regular basis and often warn readers not to jump to conclusions. Many of the recent environmental mandates are based on jumping to conclusions.
Additionally, these data are coming from institutions with names like the "Potsdam Institute for Climate Impact Research". One of the first rules of research is to eliminate bias, and ethical research demands non-politically motivated findings. However, can a scientists employed by a "Climate Impact Research" group ever be free of bias?.
My point is not to refute the findings. I am trying to point out the incongruity in the current global warming science movement. Claims that global warming proofs are "obvious" are rebutted in nearly ever peer-reviewed article. Previous predictions have been grossly wrong. There are multiple political motivations in attacking environmentally unfriendly companies as 1% protesters often turn in their anti-wall-street signage for an anti-oil-pipeline one the next weekend. Attacking evil corporations from multiple fronts doesn't just make sense, its good strategy.
I want clean air. I want clean water. I also want an economy and infrastructure that works. I want environmental policies that won't be abandoned when the predictions don't come true or when the global economy busts.
Nahor
> Before we burden our children with billions of dollars in carbon sequestering projects
Me, me, my turn to play the game of "think of the children"! Here we go: "Before burdening our children with the consequences of global warming because we didn't act fast enough, ..."
> shouldn’t we have a better understanding of the underlying science?
One can't learn anything if one doesn't want to. By selecting the pieces of evidence to fit their agenda like you just did, no amount of time can help you understand the science, you're just reinforcing your own bias.
AritzCP
Hello, we heard many words about the carbon dioxide, methane, CFCs or others, that we suppose they catch heat, but we don`t almost heard nothing about the warm water from the electrical producers, that it goes to the river, and the warm air or smokes from the engines, heats, and factories that it goes to our enviroment. Aren`t they important enough to produce the actual global warming? I think that touchable heat is very important, and we don`t almost speak about it, why? I think the trees and nature could help us, but we spend so few money in that... Bye.
Derek Howe
I 100% agree with Doubting_Thomas.
Things will & should get more efficient and less polluting, because we all have to breathe. For instance, I love electric cars, Hope to own one in a few years, but me owning one has NOTHING to do with the earth warming or cooling, its just because it's a best method to move from A to B.
Gary Bonney
Doubting_Thomas if you can not see the obvious flaws in your "arguments" then its pointless trying to logically discuss them with you.
toddzrx
Gary Bonney: please enlighten us. If you claim his reasoning is flawed, prove it. Then again, being an AGW proponent, proving anything is beneath you, I'm sure.
Bob
Probability, statistics and models are useful tools but they can be skillfully manipulated to support any preconceived bias. They can also be influenced by honestly picking the wrong variables or weighting them incorrectly. I remember the statisticians where I worked being totally outraged when I challenged their reports because I knew that the data they used was not random and had been corrupted. They also left out a critical variable in their calculations. They somehow believed that the math purified bad data. 1 + 1 may equal 2 but one apple plus one banana does not equal two watermelons. Silly example but unless you know what the numbers stand for you surely don't understand the answer.
Matt Fletcher
I will say it outright Chris Wood ( the author) has no idea what he's writing about and neither do Gary Booney, the so called scientists at the Potsdam Institute for Climate Impact Research, or the many other morons around the world stating anthropogenic-forces are responsible for global warming.
I started studying the global warming models several years ago as a hobby because I didn't know who was right and I wanted to find out for myself. So I started at the most logical place the equations/models designed predicting global warming. I quickly came to the conclusion all of the models do not accurately account for; the total energy running through our lower atmosphere, all the variables capable of disrupting these energy factors, or the lack of data to capture temperature readings around the globe prior to the 1980's (when satellites started collecting atmospheric and ground temperatures).
Both this article and the one in Scientific Reports are a farce along with most of the, "horse pucky" science used to make the claim that the globe is warming without a doubt. It's funny to see the incredibly limited number of variables they used to make these calculations, T=A+N+I (that's it really) plan stupid. Someone also please explain to me how you can get the global mean temperatures for land and ocean temperatures for the last 150 years without having any accurate data for the oceans, (which account for approximately 71% of the earth's surface,) or Antarctica prior to satellites?
I'm not saying we shouldn't reduce pollution but to say it's responsible for global warming is like saying occasional lack of sleep will lead to all people dying. People will die but to say lack of sleep is the cause of it is absurd, just like saying the reason the Earth MIGHT BE warming is due to anthropogenic-forces is absurd.
I have read a number of good articles about weather but none of them have proven conclusively whether the Earth is warming or cooling and until the experts can develop an accurately weather model that can forecast the weather more than 4 days out for the entire world I will not believe any of their models. But this is impossible. Do you know why? Because they have no idea what the sun is going to do more than 3 days out. The sun controls 95 to 98% of all energy in our lower atmosphere, the remaining being anthropogenic and geothermic energy.One direct hit from a large coronal mass ejection and that would put an end to this argument and so do I.
Gary Bonney
Toddzr ok, "Photosynthetic life appeared between 2.4 and 3.2 billion years ago, enriching the atmosphere with oxygen. Life remained mostly small and microscopic until about 580 million years ago, when complex multicellular life arose." And then "it is now generally believed that the K–Pg extinction was triggered by a massive comet or asteroid impact 66 million years ago[3] and its catastrophic effects on the global environment, including a lingering impact winter that made it impossible for plants and plankton to carry out photosynthesis.[5][6]" And then wait for the atmosphere and plant life to stabilise, then you might be heading toward a referrence date to measure from, ie. tens of millions not billions. Wikipedia as source.
"The Martian atmosphere is 100 times less dense than the atmosphere on Earth – too thin to absorb much of the outgoing heat. Mars is also further from the Sun than Earth, so it receives less solar energy." http://www.sciencemuseum.org.uk/ClimateChanging/ClimateScienceInfoZone/ExploringEarthsclimate/1point5/1point5point3.aspx
"Combustion of fossil fuels and deforestation have caused the atmospheric concentration of carbon dioxide to increase by about 43% since the beginning of the age of industrialization.[46] Most carbon dioxide from human activities is released from burning coal and other fossil fuels. Other human activities, including deforestation, biomass burning, and cement production also produce carbon dioxide." Wikipedia again.
You get the idea and why my comment about Doubting_Thomas post, most people see what they want.
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