Carl Sagan's December 1985 testimony to Congress on the greenhouse effect, about 15 minutes long. He lays out CO2 warming, the risk of runaway effects and the danger of continued coal burning.
Why Hacker News points people here: HN commenters use it as proof that the climate problem was clearly explained decades ago, and as a model of clear communication to a broad audience.
“The address Carl Sagan made in 1985 is well worth watching”HN comment, 2023
“The address Carl Sagan made in 1985 is well worth watching”
Sagan's 1985 address predicted what has since come to pass
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The address Carl Sagan made in 1985 is well worth watching for those who remember those times and especially for those who weren't alive back then [0] People knew about this before you were born and decided their best interests were more important and they acted in wilful disregard for your life and the lives of everyone on this planet. They weren't ignorant. No facts were hidden from them that they could be forgiven for being misinformed. They knew with certainty what the science was revealing and spent money to discredit the science, cut funding to their own researchers, bought politicians, funded PR campaigns, and continued building their fossil fuel empires. Everything Carl Sagan said in that address has come to pass. It's wild to watch. [0] this video
RecommendsandersonmvdJan 2022
“Look at how many details this guy (Carl Sagan) conveyed in his 15' speech”
Sagan conveys detailed content clearly to a broad audience.
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Look at how many details this guy (Carl Sagan) conveyed in his 15' speech: this video in a way that potentially everyone understood. I wonder if every explanation was like his, if nuance wouldn't be well communicated, even to large groups.
RecommendsYellowStuDreggAug 2022
“You can also watch Carl Sagan break it down in front of congress back in 1985 for just 15 minutes of your time”
Sagan explains climate science to Congress in about 15 minutes
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A quick google search gives us plenty of past published projections and how they fared: link You can also watch Carl Sagan break it down in front of congress back in 1985 for just 15 minutes of your time this video
RecommendsmellingMar 2023
“Time to watch Carl Sagan, almost 50 years ago, explain how our coal usage would be a big problem”
Sagan explaining decades ago how coal would be a big problem
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Time to watch Carl Sagan, almost 50 years ago, explain how our coal usage would be a big problem: this video A slow train wreck that was avoidable.
Cites itasix66Dec 2021
“Carl Sagan clearly explains the situation before policy makers almost 40 yrs ago”
Sagan explaining climate change to Congress in 1985.
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Almost. But those that did were not listened to as in this case where Carl Sagan clearly explains the situation before policy makers almost 40 yrs ago [1] 1: this video
Cites itjaltekruseApr 2022
“Here is Carl Sagan testifying before congress in 1985”
Sagan's 1985 congressional testimony on climate change
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I think it is important to remember that anti-renewables messaging has been around for a very long time. The panels might have needed to come off for repairs but definitely could have been put back up. Casually discarding even a public relations action like this likely had negative impacts on the discussion and many people taking the issue seriously for years to come. I don't know specifically how anti-renewables Regan was personally, but he definitely was the leader of a party that most strongly fought climate change messaging and actions in recent years. Here is Carl Sagan testifying before congress in 1985 this video Admittedly this hasn't necessarily been as strongly polarizing as it was during the 2010s, there was a time that it was a bipartisan issue that unified both parties in the interest of reducing foreign energy dependence. link
Cites itmellingMay 2022
“He said China would use all that coal and they did.”
Sagan's early warning about coal use and China
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It’s 2022 and 40% of global electricity is from coal. We just hit 10% from solar and wind. Here’s Carl Sagan from 1985: this video He said China would use all that coal and they did. We lost decades of time. Now we need a few additional miracles.
Cites itmellingJul 2022
“Carl Sagan understood the issues so well.”
Sagan understood climate issues decades ago
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Sounds more like a long-term plan… “It will take €10 trillion of investment by 2050 for Europe to transform its energy infrastructure” In case anyone is wondering how we got here, it required almost 40 years of not doing much to solve the problem. We’ll need another 30 years of effort. I imagine because we waited so long, we shortened our window to solve the problem. Thus requiring more money and a couple additional miracles. The multi-generational effort did turn out to be a problem. And all that coal in China. Carl Sagan understood the issues so well. this video
Cites itmellingSep 2022
“Carl Sagan warned us almost 40 years ago that coal would be a future problem.”
Sagan warned decades ago that coal would be a problem
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That’s not correct. There are large emission issues that would should tackle first. How we generate electricity is one of them. Carl Sagan warned us almost 40 years ago that coal would be a future problem. this video That was clearly a large problem that could have been addressed, and still needs to be ASAP. Coal-fired power stations emit over 10 Gt of carbon dioxide each year,[4] about one fifth of world greenhouse gas emissions, so are the single largest cause of climate change. 8500 coal power plants in the world. “Coal-fired power stations emit over 10 Gt of carbon dioxide each year,[4] about one fifth of world greenhouse gas emissions, so are the single largest cause of climate change.” link So, we start the discussion with air travel, trying to reduce 2% to under 2%. While we’ve ignored 20% of global emissions. We actually cost ourselves decades. So many miracles needed by 2050, when we could be talking 2070. Now, let’s just tell everyone we need to do everything at once.
Cites itmellingOct 2022
“we were warned 40 years ago about global coal use.”
Warning about global coal use given 40 years ago
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I hear all kinds of narratives on this. According to this EPA article, US emissions are down 20% since 2005. link Of course, global emissions are way up but we were warned 40 years ago about global coal use. this video
Cites itmellingApr 2023
“Carl Sagan warned everyone about coal 40 years ago.”
Sagan warned about coal long before aviation debates
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100,000 flights a day, every single day of the year 2% of emissions. Coal power plants 25% of emissions. So many people going after aviation, it explains how we got this far into the problem. Carl Sagan warned everyone about coal 40 years ago. this video So, instead we talk about aviation
Cites ithn8305823May 2023
“5 years later he testified to Congress about the dangers of excess CO2 emissions causing runaway warming”
Sagan's 1985 testimony on CO2 and runaway warming
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Here is Carl Sagan's original essay on climate change in 1980 where he warned specifically about global cooling based on deforestation: link 5 years later he testified to Congress about the dangers of excess CO2 emissions causing runaway warming : this video On the surface these two messages may seem contradictory but underlying both is a consistent message that excessive man-made changes to a delicate highly non-linear system are dangerous to our survival as a species.
Cites it2479411230May 2023
“See, for example, Carl Sagan testifying before Congress in 1985”
Example of calm, non-panicked climate warnings long ago
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> Can we explore this issue from a not-panicked perspective? I think we tried doing that. See, for example, Carl Sagan testifying before Congress in 1985 [1]. I _wish_ that fossil fuels could be on your list. I think a main reason why nothing is being done is that oil is big business! Oil companies have toppled a democratically elected government because that government was cutting into their oil profits [2]. Moving away from fossil fuels would cut into oil's bottom line, so they paid lots of money to discredit and oppose climate change research for decades [3]. [1]: this video [2]: link [3]: link
Cites itmellingJun 2023
“We were warned about the coal problem in China/India 40 years ago.”
Sagan warned about coal in China and India
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We were warned about the coal problem in China/India 40 years ago. this video We were also warned that even if the United States solved the problem that it wasn’t enough. People think they can convince several billion people to give up meat but replacing several thousand coal power plants is too hard… “Local governments in China approved more new coal power in the first three months of 2023 than in the whole of 2021, according to official documents” link
Cites itmellingAug 2023
“One of the main problems was identified in 1985.”
Main climate problems were identified in 1985
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“Gotta start somewhere” We’re about 40 years into “getting started”. One of the main problems was identified in 1985. this video
Cites itojosilvaAug 2023
“That's Al Gore at 11:28.”
Points out Al Gore's participation in the hearing
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That's Al Gore at 11:28. this video If you watch the entire video, you'll see he's actively involved on this committee presentation, arguments and deliberation. link
Cites itmellingJul 2024
“Carl Sagan nailed it”
Sagan's accurate predictions about climate
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How have we done in the last 40 years dealing with climate change? Peak fossil fuels Real Soon Now I’d say Carl Sagan nailed it: this video
Cites itmellingSep 2024
“40 years ago Carl Sagan said to stop burning coal and make sure India and China don’t use all their reserves.”
Sagan urged stopping coal burning decades ago
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40 years ago Carl Sagan said to stop burning coal and make sure India and China don’t use all their reserves. Imagine how much more time we would have if we’d have listened. this video We should be very close to peak coal sometime this decade.
Cites itmellingJun 2025
“We’ve had 40 years and we’re still burning all the coal Carl Sagan warned us about.”
Sagan warned about coal forty years ago
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We’ve had 40 years and we’re still burning all the coal Carl Sagan warned us about. this video So, after 40 years I’m a little tired of hearing it takes too long to build nuclear power plants. On the bright side, we’ve almost reached peak coal: link
Cites itmetobehonestMar 2026
“I'm sure Carl Sagan was a just whiny loser because he didn't figure out how to become a billionaire from knowing how physics works.”
Sagan's climate predictions cited against dismissing doomers
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>If doomers were good at predicting these events and how it will play out they'd all be rich as hell, but no, they are for the most part a bunch of broke whiners. Oh, the classic "if you're so smart then why aren't you rich" non argument. I'm sure Carl Sagan was a just whiny loser because he didn't figure out how to become a billionaire from knowing how physics works. His prediction that the planet would warm several degrees by the mid to late 21st century failed to reward him what he was owed. By the way we haven't even gotten halfway there yet, so your "shifting goalposts" thesis is null. People who push dangerous neoliberal propaganda like carbon capture or "infinite growth on a finite planet is possible" on the other hand do get very rich, and they don't even need to make good predictions. Such is the planet governed by pedophiles. this video