Global warming is happening | |||
Fact | Myth | Fallacy | Video |
Our planet has continued to build up heat since 1998 - global warming is still happening. | "Global warming stopped in 1998." | Cherry picking Looking at one region or a short period ignores the full picture. |
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Global warming is like rigging the weather dice, making it more likely to get hot days. | "It's cold outside, so global warming must have stopped." | Impossible Expectations Global warming doesn't mean no more cold weather, just fewer cold days compared to hot days. |
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Overall, glaciers across the globe are shrinking at an accelerating rate, threatening water supplies for millions of people. | "Glaciers around the world are increasing, disproving global warming." | Cherry picking Picking a handful of growing glaciers ignores the vast majority of glaciers that are shrinking. |
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Greenland on the whole is losing ice, at a rate of over 2 Mount Everests worth of ice every year. | "Greenland Ice sheet is thick- ening in the middle so it must be gaining mass." | Cherry picking Looking at the whole ice sheet shows it's thickening in the middle but ice loss at the edges is accelerating. |
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The West Antarctic ice sheet is losing hundreds of billions of tonnes of ice every year, making it a major contributor to global sea level rise. | "Antarctic sea ice is on the increase and casts doubt on global warming." | Over-simplification A number of factors may contribute to the increase in sea ice - but in no way does it change the fact that climate change is happening. |
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We can measure temperature in many ways and they all say the same thing - our planet is warming. | "The thermometer record is unreliable." | Jumping to conclusions Just because measurements have uncertainty doesn't mean it's unknowable. The uncertainty is smaller than measured global warming. |
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Urban heat has had minimal effect on the climate record, with much warming happening where there is little urban development. | "Urban development is responsible for much of global warming over the last century." | Jumping to conclusions Just because urban heat might affect the climate record doesn't mean it does. Scientists have confirmed it has neglible effect. |
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Slowing jet stream is causing Arctic cold air to leak down into Europe and North America, like an open fridge leaking cold air into the kitchen. | "Record cold winters disprove global warming." | Jumping to conclusions A cold winter doesn't disprove global warming, you need to look at the big picture. |
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Climate change and global warming have both been used for decades. | "They changed name from ‘global warming’ to ‘climate change’." | Misrepresentation They didn't change the name. |
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We're causing global warming | |||
Fact | Myth | Fallacy | Video |
For thousands of years, our atmosphere has been in balance. Humans have upset the balance. | "Human CO2 emissions are tiny compared to natural CO2 emissions so our influence is negligible." | Over-simplification Considers only natural CO2 emissions and ignores natural CO2 sinks. |
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Human emissions are responsible for all of the increase in CO2 in the air over the past two centuries. | "Volcanoes produce more CO2 than humans." | Jumping to conclusions Volcanoes do produce CO2, but over recent centuries the amounts are too small to account for the observed changes in the air. |
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If we stopped emitting CO2, it would take thousands of years for the atmosphere to return to pre-industrial levels. | "CO2 has a residence time of only 4 years so CO2 levels would fall quickly if we stopped emitting." | Red herring How quickly a CO2 molecule moves around the climate system is different to how long it takes CO2 level to return back to normal. |
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Greenhouse gases are like a blanket. They trap heat, sending it back down to Earth where we measure it. | "Greenhouse effect violates the 2nd law of thermodynamics." | Misrepresentation 2nd law talks about net flow of energy and doesn't forbid some flow from cool to hot. |
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Emitting more CO2 means more heat is being trapped high up in the atmosphere where the air is thinner. | "The greenhouse effect is saturated so adding more CO2 won't affect it." | Over-simplification Considers atmosphere as a single layer when it's multiple layers. |
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Ice cores tell us warming causes the ocean to emit more CO2. Combined with greenhouse effect, this is a reinforcing feedback. | "CO2 lagging temperature means greenhouse effect is minimal." | False dichotomy it's not one or the other but both. CO2 causes warming and warming causes CO2 to rise. |
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One human fingerprint is a cooling upper atmosphere with a warming lower atmosphere. Satellites have measured this pattern. | "One fingerprint of human-caused global warming is the tropospheric hot spot which hasn't been observed." | Red herring The hot spot is irrelevant to greenhouse warming. |
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Satellites measure the warming effect from CO2. The increased greenhouse effect is an observed reality. | "CO2 is a trace gas so its warming effect is minimal." | Red herring Trace amounts of substances can have a strong effect and this is irrelevant to the warming potential of CO2. |
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Changing patterns in the yearly and daily cycle confirm human-caused global warming, rule out the sun. | "The sun is causing global warming." | Cherry picking Ignores human fingerprints and recent period where sun and climate move in opposite directions. |
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Past and future climate change | |||
Fact | Myth | Fallacy | Video |
Past climate change tells us climate is sensitive to the warming effect of CO2. | "Natural climate change in the past implies current climate change is also natural." | Jumping to conclusions Past climate change actually sends the opposite message than what the myth concludes. |
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Natural influences that ended the Little Ice Age have been swamped by recent human activity. | "Current warming is just the continuation of natural recovery from the Little Ice Age." | Red herring The natural factors that ended the Little Ice Age are no longer significant. |
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In the past when the sun was cooler, CO2 was higher. The two roughly balanced each other. We are now raising CO2 levels with a warmer sun. | "CO2 was higher in the past but the world didn't boil away so the greenhouse effect is weak." | Cherry picking Ignores the role of the sun which was cooler in the past. |
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While the Medieval Warm Period saw unusually warm temperatures in some regions, globally the planet was cooler than now. | "The Medieval Warm Period was warmer than current conditions. This implies recent warming is not unusual and must be natural." | Cherry picking For average temperature over wide regions, the hot regions were cancelled out by other cool regions. |
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Models are based on fundamental physical principles. | "Models are unreliable." | Impossible Expectations No model is perfect but they are useful tools that can reproduce the past and provide insights into the future. |
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Models have made a number of successful predictions. | "Models predictions have failed, making them unreliable." | Impossible Expectations Climate models have had great success at predicting long-term effects like greenhouse warming. |
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Climate models simulate climate which is weather averaged over time. | "Scientists can’t even predict weather." | Red herring Confusing weather with climate distracts from the fact that short-term predictions have little relevance to long-term climate predictions. |
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In the 1970s, the majority of climate papers were predicting warming. | "In the 1970s, climate scientists were predicting an ice age." | Misrepresentation Confuses mainstream media reports with scientific papers which over- whelmingly pointed towards warming. |
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Even if the sun fell to Maunder Minimum levels, it would only delay global warming by a decade. | "We're heading into another ice age because of the cooling sun." | Misrepresentation Overstating the role of solar activity on climate - it actually has had little effect. |
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The IPCC is 20 times more likely to underestimate rather than exagerate climate impacts. | "Climate models and the IPCC are alarmist." | Cherry picking Selectively looks at a few examples where the IPCC overestimated climate change, ignoring the much larger number of examples of underestimation. |
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Climate impacts | |||
Fact | Myth | Fallacy | Video |
The amount of water vapor in the air depends on temperature. Warming causes water vapor to rise, which causes further warming: a reinforcing feedback. | "Water vapor is the strongest greenhouse gas so CO2 emissions don't matter." | Red herring The fact that water vapor is a strong greenhouse gas means it amplifies the warming from greenhouse gases. |
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Clouds provide a reinforcing feedback but the effect isn't strong . Clouds play a minor role in climate sensitivity. | "Clouds provide negative feedback." | Over-simplification Acting as if clouds only have a cooling effect ignores that they can also warm. |
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Mass extinctions happen when climate changes too fast for species to adapt. Currently species are going extinct at similar rates to past mass extinctions. | "Species can adapt to climate change." | Misrepresentation Just because species can adapt to some climate change doesn’t mean they can adjust to the rapid climate change happening now. |
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Polar bears need sea ice to hunt so the shrinking of Arctic sea ice is endangering their populations. | "Polar bear numbers have increased so they're in no danger from global warming." | Over-simplification One threat (hunting) has been removed but replaced with an increasing threat (melting sea ice). |
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Ocean acidity has increased 30% and poses serious threats to coral reefs that are also threatened by warming oceans and bleaching. | "Ocean acidification isn’t serious." | Misrepresentation Ocean acidification means oceans are decreasing in pH so they are getting more acidic, even if they are not actually acid. |
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Climate change is having negative impacts on all parts of society. | "Global warming is good." | Cherry picking This focuses on a few good impacts of global warming but ignores the overwhelming number of bad impacts. |
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A pollutant is any substance that disrupts the environment - CO2 does that by trapping heat. | "CO2 is not a pollutant." | Red herring Quibbling over technical definitions of pollut- ant is a distraction from the realities of the negative impacts of global warming. |
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Climate change impacts agriculture through extreme weather: heat stress and flooding. | "CO2 is plant food." | Over-simplification CO2 fertilisation is just one factor affecting plant growth. The full picture shows that negative impacts outweigh benefits. |
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Risk from extreme weather is increasing, albeit some forms of extreme weather are more confidently linked to global warming than others. | "Extreme weather not linked to global warming." | Jumping to conclusions Just because extreme weather happened in the past doesn’t mean climate change isn’t having an influence now. |