Progressives should know the disinformers’ most commonly used arguments — and how to answer them crisply. Those arguments have been repeated so many times by the fossil-fuel-funded disinformation campaign that almost everyone has heard them — and that means you’ll have to deal with them in almost any setting, from a public talk to a dinner party. You should also know as much of the science behind those rebuttals as possible, and a great place to start is SkepticalScience.com. BUT most of the time your best response is to give the pithiest response possible, and then refer people to a specific website that has a more detailed scientific explanation with links to the original science. That’s because usually those you are talking to are rarely in a position to adjudicate scientific arguments. Indeed, they would probably tune out. Also, unless you know the science cold, you are as likely as not to make a misstatement. Physicist John Cook has done us a great service by posting good one-line responses and then updating them as the science evolves and as people offer better ways of phrasing. Below I have reposted the top 99 with links to the science. You can find even more here. Everybody should know the first 20 or so. For instance, if somebody raises the standard talking point (#1 on the list) that the “climate’s changed before,” you can say, “Climate reacts to whatever forces it to change at the time; humans are now the dominant forcing.” That is actually quite similar to what was my standard response, “The climate changes when it is forced to change, and now humans are forcing it to change far more rapidly than it did in the past” (see “Humans boosting CO2 14,000 times faster than nature, overwhelming slow negative feedbacks” and “New Science Study Confirms ‘Hockey Stick’: The Rate Of Warming Since 1900 Is 50 Times Greater Than The Rate Of Cooling In Previous 5000 Years“). Working in the “humans are now the dominant forcing” part is a good idea. Cook explains the origin of these one-liners in a 2010 post, “Rebutting skeptic arguments in a single line.” I have included the longer ‘paragraph’ rebuttals, which any CP reader who plans to speak out on this subject — in public or just with friends and associates — should also be familiar with. Skeptic Rebuttal One Liners Skeptic Argument One Liner Paragraph 1 “Climate’s changed before” Climate reacts to whatever forces it to change at the time; humans are now the dominant forcing. 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. 2 “It’s the sun” In the last 35 years of global warming, sun and climate have been going in opposite directions In the last 35 years of global warming, the sun has shown a slight cooling trend. Sun and climate have been going in opposite directions. 3 “It’s not bad” Negative impacts of global warming on agriculture, health & environment far outweigh any positives. The negative impacts of global warming on agriculture, health, economy and environment far outweigh any positives. 4 “There is no consensus” 97% of climate experts agree humans are causing global warming. That humans are causing global warming is the position of the Academies of Science from 19 countries plus many scientific organizations that study climate science. More specifically, around 95% of active climate researchers actively publishing climate papers endorse the consensus position. 5 “It’s cooling” The last decade 2000-2009 was the hottest on record. Empirical measurements of the Earth’s heat content show the planet is still accumulating heat and global warming is still happening. Surface temperatures can show short-term cooling when heat is exchanged between the atmosphere and the ocean, which has a much greater heat capacity than the air. 6 “Models are unreliable” Models successfully reproduce temperatures since 1900 globally, by land, in the air and the ocean. While there are uncertainties with climate models, they successfully reproduce the past and have made predictions that have been subsequently confirmed by observations. 7 “Temp record is unreliable” The warming trend is the same in rural and urban areas, measured by thermometers and satellites. Numerous studies into the effect of urban heat island effect and microsite influences find they have negligible effect on long-term trends, particularly when averaged over large regions. 8 “Animals and plants can adapt” Global warming will cause mass extinctions of species that cannot adapt on short time scales. A large number of ancient mass extinction events have been strongly linked to global climate change. Because current climate change is so rapid, the way species typically adapt (eg – migration) is, in most cases, simply not be possible. Global change is simply too pervasive and occurring too rapidly. 9 “It hasn’t warmed since 1998″ For global records, 2010 is the hottest year on record, tied with 2005. The planet has continued to accumulate heat since 1998 – global warming is still happening. Nevertheless, surface temperatures show much internal variability due to heat exchange between the ocean and atmosphere. 1998 was an unusually hot year due to a strong El Nino. 10 “Antarctica is gaining ice” Satellites measure Antarctica losing land ice at an accelerating rate. While the interior of East Antarctica is gaining land ice, overall Antarctica is losing land ice at an accelerating rate. Antarctic sea ice is growingdespite a strongly warming Southern Ocean. 11 “Ice age predicted in the 70s” The vast majority of climate papers in the 1970s predicted warming. 1970s ice age predictions were predominantly media based. The majority of peer reviewed research at the time predicted warming due to increasing CO2. 12 “CO2 lags temperature” CO2 didn’t initiate warming from past ice ages but it did amplify the warming. When the Earth comes out of an ice age, the warming is not initiated by CO2 but by changes in the Earth’s orbit. The warming causes the oceans to give up CO2. The CO2 amplifies the warming and mixes through the atmosphere, spreading warming throughout the planet. So CO2 causes warming AND rising temperature causes CO2 rise. 13 “Climate sensitivity is low” Net positive feedback is confirmed by many different lines of evidence. Climate sensitivity can be calculated empirically by comparing past temperature change to natural forcings at the time. Various periods of Earth’s past have been examined in this manner and find broad agreement of a climate sensitivity of around 3°C. 14 “We’re heading into an ice age” Worry about global warming impacts in the next 100 years, not an ice age in over 10,000 years. The warming effect from more CO2 greatly outstrips the influence from changes in the Earth’s orbit or solar activity, even if solar levels were to drop to Maunder Minimum levels. 15 “Ocean acidification isn’t serious” Ocean acidification threatens entire marine food chains. Past history shows that when CO2 rose sharply, this corresponded with mass extinctions of coral reefs. Currently, CO2 levels are rising faster than any other time in known history. The change in seawater pH over the 21st Century is projected to be faster than anytime over the last 800,000 years and will create conditions not seen on Earth for at least 40 million years. 16 “Hockey stick is broken” Recent studies agree that recent global temperatures are unprecedented in the last 1000 years. Since the hockey stick paper in 1998, there have been a number of proxy studies analysing a variety of different sources including corals, stalagmites, tree rings, boreholes and ice cores. They all confirm the original hockey stick conclusion: the 20th century is the warmest in the last 1000 years and that warming was most dramatic after 1920. 17 “Climategate CRU emails suggest conspiracy” A number of investigations have cleared scientists of any wrongdoing in the media-hyped email incident. While some of the private correspondance is not commendable, an informed examination of their ‘suggestive’ emails reveal technical discussions using techniques well known in the peer reviewed literature. Focusing on a few suggestive emails merely serves to distract from the wealth of empirical evidence for man-made global warming. 18 “Hurricanes aren’t linked to global warming” There is increasing evidence that hurricanes are getting stronger due to global warming. It is unclear whether global warming is increasing hurricane frequency but there is increasing evidence that warming increases hurricane intensity. 19 “Al Gore got it wrong” Al Gore book is quite accurate, and far more accurate than contrarian books. While there are minor errors in An Inconvenient Truth, the main truths presented – evidence to show mankind is causing global warming and its various impacts is consistent with peer reviewed science. 20 “Glaciers are growing” Most glaciers are retreating, posing a serious problem for millions who rely on glaciers for water. While there are isolated cases of growing glaciers, the overwhelming trend in glaciers worldwide is retreat. In fact, the global melt rate has been accelerating since the mid-1970s. 21 “It’s cosmic rays” Cosmic rays show no trend over the last 30 years & have had little impact on recent global warming. While the link between cosmic rays and cloud cover is yet to be confirmed, more importantly, there has been no correlation between cosmic rays and global temperatures over the last 30 years of global warming. 22 “1934 – hottest year on record” 1934 was one of the hottest years in the US, not globally. 1934 is the hottest year on record in the USA which only comprises 2% of the globe. According to NASA temperature records, the hottest year on record globally is 2005. 23 “It’s freaking cold!” A local cold day has nothing to do with the long-term trend of increasing global temperatures. Since the mid 1970s, global temperatures have been warming at around 0.2 degrees Celsius per decade. However, weather imposes its own dramatic ups and downs over the long term trend. We expect to see record cold temperatures even during global warming. Nevertheless over the last decade, daily record high temperatures occurred twice as often as record lows. This tendency towards hotter days is expected to increase as global warming continues into the 21st Century. 24 “Sea level rise is exaggerated” A variety of different measurements find steadily rising sea levels over the past century. Sea levels are measured by a variety of methods that show close agreement – sediment cores, tidal gauges, satellite measurements. What they find is sea level rise has been steadily accelerating over the past century. 25 “It’s Urban Heat Island effect” Urban and rural regions show the same warming trend. While urban areas are undoubtedly warmer than surrounding rural areas, this has had little to no impact on warming trends. 26 “Medieval Warm Period was warmer” Globally averaged temperature now is higher than global temperature in medieval times. While the Medieval Warm Period saw unusually warm temperatures in some regions, globally the planet was cooler than current conditions. 27 “Mars is warming” Mars is not warming globally. Martian climate is primarily driven by dust and albedo and there is little empirical evidence that Mars is showing long term warming. 28 “Arctic icemelt is a natural cycle” Thick arctic sea ice is undergoing a rapid retreat. Arctic sea ice has been retreating over the past 30 years. The rate of retreat is accelerating and in fact is exceeding most models’ forecasts. 29 “Increasing CO2 has little to no effect” The strong CO2 effect has been observed by many different measurements. An enhanced greenhouse effect from CO2 has been confirmed by multiple lines of empirical evidence. Satellite measurements of infrared spectra over the past 40 years observe less energy escaping to space at the wavelengths associated with CO2. Surface measurements find more downward infrared radiation warming the planet’s surface. This provides a direct, empirical causal link between CO2 and global warming. 30 “Oceans are cooling” The most recent ocean measurements show consistent warming. Early estimates of ocean heat from the Argo showed a cooling bias due to pressure sensor issues. Recent estimates of ocean heat that take this bias into account show continued warming of the upper ocean. This is confirmed by independent estimates of ocean heat as well as more comprehensive measurements of ocean heat down to 2000 metres deep. 31 “Human CO2 is a tiny % of CO2 emissions” The natural cycle adds and removes CO2 to keep a balance; humans add extra CO2 without removing any. The CO2 that nature emits (from the ocean and vegetation) is balanced by natural absorptions (again by the ocean and vegetation). Therefore human emissions upset the natural balance, rising CO2 to levels not seen in at least 800,000 years. In fact, human emit 26 gigatonnes of CO2 per year while CO2 in the atmosphere is rising by only 15 gigatonnes per year – much of human CO2 emissions is being absorbed by natural sinks. 32 “IPCC is alarmist” Numerous papers have documented how IPCC predictions are more likely to underestimate the climate response. The IPCC lead authors are experts in their field, instructed to fairly represent the full range of the up-to-date, peer-reviewed literature. Consequently, the IPCC reports tend to be cautious in their conclusions. Comparisons to the most recent data consistently finds that climate change is occurring more rapidly and intensely than indicated by IPCC predictions. 33 “Water vapor is the most powerful greenhouse gas” Rising CO2 increases atmospheric water vapor, which makes global warming much worse. Water vapour is the most dominant greenhouse gas. Water vapour is also the dominant positive feedback in our climate system and amplifies any warming caused by changes in atmospheric CO2. This positive feedback is why climate is so sensitive to CO2 warming. 34 “Polar bear numbers are increasing” Polar bears are in danger of extinction as well as many other species. While there is some uncertainty on current polar bear population trends, one thing is certain. No sea ice means no seals which means no polar bears. With Arctic sea ice retreating at an accelerating rate, the polar bear is at grave risk of extinction 35 “CO2 limits will harm the economy” The benefits of a price on carbon outweigh the costs several times over. Economic assessments of proposed policy to put a price on carbon emissions are in widespread agreement that the net economic impact will be minor. The costs over the next several decades center around $100 per average family, or about 75 cents per person per day, and a GDP reduction of less than 1%. 36 “It’s not happening” There are many lines of evidence indicating global warming is unequivocal. There are many lines of independent empirical evidence for global warming, from accelerated ice loss from the Arctic to Antarctica to the poleward migration of plant and animal species across the globe. 37 “Greenland was green” Other parts of the earth got colder when Greenland got warmer. The Greenland ice sheet has existed for at least 400,000 years. There may have been regions of Greenland that were ‘greener’ than today but this was not a global phenomenon. 38 “Greenland is gaining ice” Greenland on the whole is losing ice, as confirmed by satellite measurement. While the Greenland interior is in mass balance, the coastlines are losing ice. Overall Greenland is losing ice mass at an accelerating rate. From 2002 to 2009, the rate of ice mass loss doubled. 39 “CO2 is not a pollutant” Through its impacts on the climate, CO2 presents a danger to public health and welfare, and thus qualifies as an air pollutant While there are direct ways in which CO2 is a pollutant (acidification of the ocean), its primary impact is its greenhouse warming effect. While the greenhouse effect is a natural occurence, too much warming has severe negative impacts on agriculture, health and environment. 40 “CO2 is plant food” The effects of enhanced CO2 on terrestrial plants are variable and complex and dependent on numerous factors The effects of enhanced CO2 on terrestrial plants are variable and complex and dependent on numerous factors 41 “Other planets are warming” Mars and Jupiter are not warming, and anyway the sun has recently been cooling slightly. There are three fundamental flaws in the ‘other planets are warming’ argument. Not all planets in the solar system are warming. The sun has shown no long term trend since 1950 and in fact has shown a slight cooling trend in recent decades. There are explanations for why other planets are warming. 42 “Arctic sea ice has recovered” Thick arctic sea ice is in rapid retreat. Arctic sea ice has been steadily thinning, even in the last few years while the surface ice (eg – sea ice extent) increased slightly. Consequently, the total amount of Arctic sea ice in 2008 and 2009 are the lowest on record. 43 “There’s no empirical evidence” There are multiple lines of direct observations that humans are causing global warming. Direct observations find that CO2 is rising sharply due to human activity. Satellite and surface measurements find less energy is escaping to space at CO2 absorption wavelengths. Ocean and surface temperature measurements find the planet continues to accumulate heat. This gives a line of empirical evidence that human CO2 emissions are causing global warming. 44 “We’re coming out of the Little Ice Age” Scientists have determined that the factors which caused the Little Ice Age cooling are not currently causing global warming The main driver of the warming from the Little Ice Age to 1940 was the warming sun with a small contribution from volcanic activity. However, solar activity leveled off after 1940 and the net influence from sun and volcano since 1940 has been slight cooling. Greenhouse gases have been the main contributor of warming since 1970. 45 “There’s no correlation between CO2 and temperature” There is long-term correlation between CO2 and global temperature; other effects are short-term. Even during a period of long term warming, there are short periods of cooling due to climate variability. Short term cooling over the last few years is largely due to a strong La Nina phase in the Pacific Ocean and a prolonged solar minimum. 46 “It cooled mid-century” Mid-century cooling involved aerosols and is irrelevant for recent global warming. There are a number of forcings which affect climate (eg – stratospheric aerosols, solar variations). When all forcings are combined, they show good correlation to global temperature throughout the 20th century including the mid-century cooling period. However, for the last 35 years, the dominant forcing has been CO2. 47 “CO2 was higher in the past” When CO2 was higher in the past, the sun was cooler. When CO2 levels were higher in the past, solar levels were also lower. The combined effect of sun and CO2 matches well with climate. 48 “It warmed before 1940 when CO2 was low” Early 20th century warming is due to several causes, including rising CO2. Early 20th century warming was in large part due to rising solar activity and relatively quiet volcanic activity. However, both factors have played little to no part in the warming since 1975. Solar activity has been steady since the 50′s. Volcanoes have been relatively frequent and if anything, have exerted a cooling effect. 49 “Global warming stopped in 1998,1995, 2002,2007, 2010, ????” Global temperature is still rising and 2010 was the hottest recorded. 2007′s dramatic cooling is driven by strong La Nina conditions which historically has caused similar drops in global temperature. It is also exacerbated by unusually low solar activity. 50 “Satellites show no warming in the troposphere” The most recent satellite data show that the earth as a whole is warming. Satellite measurements match model results apart from in the tropics. There is uncertainty with the tropical data due to how various teams correct for satellite drift. The U.S. Climate Change Science Program concludes the discrepancy is most likely due to data errors. 51 “It’s aerosols” Aerosols have been masking global warming, which would be worse otherwise. The global dimming trend reversed around 1990 – 15 years after the global warming trend began in the mid 1970′s. 52 “It’s El Niño” El Nino has no trend and so is not responsible for the trend of global warming. The El Nino Southern Oscillation shows close correlation to global temperatures over the short term. However, it is unable to explain the long term warming trend over the past few decades. 53 “2009-2010 winter saw record cold spells” A cold day in Chicago in winter has nothing to do with the trend of global warming. The cold snap is due to a strong phase of the Arctic Oscillation. This is causing cool temperatures at mid-latitudes (eg – Eurasia and North America) and warming in polar regions (Greenland and Arctic Ocean). The warm and cool regions roughly balance each other out with little impact on global temperature. 54 “It’s a natural cycle” No known natural forcing fits the fingerprints of observed warming except anthropogenic greenhouse gases. A natural cycle requires a forcing, and no known forcing exists that fits the fingerprints of observed warming – except anthropogenic greenhouse gases. 55 “Mt. Kilimanjaro’s ice loss is due to land use” Most glaciers are in rapid retreat worldwide, notwithstanding a few complicated cases. Mount Kilimanjaro’s shrinking glacier is complicated and not due to just global warming. However, this does not mean the Earth is not warming. There is ample evidence that Earth’s average temperature has increased in the past 100 years and the decline of mid- and high-latitude glaciers is a major piece of evidence. 56 “There’s no tropospheric hot spot” We see a clear “short-term hot spot” – there’s various evidence for a “long-term hot spot”. Satellite measurements match model results apart from in the tropics. There is uncertainty with the tropic data due to how various teams correct for satellite drift. The U.S. Climate Change Science Program conclude the discrepancy is most likely due to data errors. 57 “It’s not us” Multiple sets of independent observations find a human fingerprint on climate change. The human fingerprint in global warming is evident in multiple lines of empirical evidence – in satellite measurements of outgoing infrared radiation, in surface measurements of downward infrared radiation, in the cooling stratosphere and other metrics. 58 “It’s Pacific Decadal Oscillation” The PDO shows no trend, and therefore the PDO is not responsible for the trend of global warming. PDO as an oscillation between positive and negative values shows no long term trend, while temperature shows a long term warming trend. When the PDO last switched to a cool phase, global temperatures were about 0.4C cooler than currently. The long term warming trend indicates the total energy in the Earth’s climate system is increasing due to an energy imbalance. 59 “IPCC were wrong about Himalayan glaciers” Glaciers are in rapid retreat worldwide, despite 1 error in 1 paragraph in a 1000 page IPCC report. The IPCC error on the 2035 prediction was unfortunate and it’s important that such mistakes are avoided in future publications through more rigorous review. But the central message of the IPCC AR4, is confirmed by the peer reviewed literature. The Himalayan glaciers are of vital importance, providing drinking water to half a billion people. Satellites and on-site measurements are observing that Himalayan glaciers are disappearing at an accelerating rate. 60 “Scientists can’t even predict weather” Weather and climate are different; climate predictions do not need weather detail. Weather is chaotic, making prediction difficult. However, climate takes a long term view, averaging weather out over time. This removes the chaotic element, enabling climate models to successfully predict future climate change. 61 “Greenhouse effect has been falsified” The greenhouse effect is standard physics and confirmed by observations. The atmosphere of the Earth is less able to absorb shortwave radiation from the Sun than thermal radiation coming from the surface. The effect of this disparity is that thermal radiation escaping to space comes mostly from the cold upper atmosphere, while the surface is maintained at a substantially warmer temperature. This is called the “atmospheric greenhouse effect”, and without it the Earth’s surface would be much colder. 62 “2nd law of thermodynamics contradicts greenhouse theory” The 2nd law of thermodynamics is consistent with the greenhouse effect which is directly observed. The atmosphere of the Earth is less able to absorb shortwave radiation from the Sun than thermal radiation coming from the surface. The effect of this disparity is that thermal radiation escaping to space comes mostly from the cold upper atmosphere, while the surface is maintained at a substantially warmer temperature. This is called the “atmospheric greenhouse effect”, and without it the Earth’s surface would be much colder. 63 “The science isn’t settled” That human CO2 is causing global warming is known with high certainty & confirmed by observations. Science is never 100% settled – science is about narrowing uncertainty. Different areas of science are understood with varying degrees of certainty. For example, we have a lower understanding of the effect of aerosols while we have a high understanding of the warming effect of carbon dioxide. Poorly understood aspects of climate change do not change the fact that a great deal of climate science is well understood. 64 “Clouds provide negative feedback” Evidence is building that net cloud feedback is likely positive and unlikely to be strongly negative. Although the cloud feedback is one of the largest remaining uncertainties in climate science, evidence is building that the net cloud feedback is likely positive, and unlikely to be strongly negative. 65 “Sea level rise predictions are exaggerated” Sea level rise is now increasing faster than predicted due to unexpectedly rapid ice melting. Observed sea levels are actually tracking at the upper range of the IPCC projections. When accelerating ice loss from Greenland and Antarctica are factored into sea level projections, the estimated sea level rise by 2100 is between 75cm to 2 metres. 66 “It’s the ocean” The oceans are warming and moreover are becoming more acidic, threatening the food chain. Oceans are warming across the globe. In fact, globally oceans are accumulating energy at a rate of 4 x 1021 Joules per year – equivalent to 127,000 nuclear plants (which have an average output of 1 gigawatt) pouring their energy directly into the world’s oceans. This tells us the planet is in energy imbalance – more energy is coming in than radiating back out to space. 67 “IPCC were wrong about Amazon rainforests” The IPCC statement on Amazon rainforests was correct, and was incorrectly reported in some media. The IPCC statement on Amazon rain forests is correct. The error was incorrect citation, failing to mention the peer-reviewed papers where the data came from. The peer-reviewed science prior to the 2007 IPCC report found that up to 40% of the Brazilian forest is vulnerable to drought. Subsequent field research has confirmed this assessment. 68 “Corals are resilient to bleaching” Globally about 1% of coral is dying out each year. On a world scale coral reefs are in decline. Over the last 30-40 years 80% of coral in the Caribbean have been destroyed and 50% in Indonesia and the Pacific. Bleaching associated with the 1982 -1983 El-Nino killed over 95% of coral in the Galapagos Islands and the 1997-1998 El-Nino alone wiped out 16% of all coral on the planet. Globally about 1% of coral is dying out each year. 69 “Volcanoes emit more CO2 than humans” Humans emit 100 times more CO2 than volcanoes. Volcanoes emit around 0.3 billion tonnes of CO2 per year. This is about 1% of human CO2 emissions which is around 29 billion tonnes per year. 70 “CO2 effect is saturated” Direct measurements find that rising CO2 is trapping more heat. If the CO2 effect was saturated, adding more CO2 should add no additional greenhouse effect. However, satellite and surface measurements observe an enhanced greenhouse effect at the wavelengths that CO2 absorb energy. This is empirical proof that the CO2 effect is not saturated. 71 “Greenland ice sheet won’t collapse” When Greenland was 3 to 5 degrees C warmer than today, a large portion of the Ice Sheet melted. Satellite gravity measurements show Greenland is losing ice mass at an accelerated rate, increasing its contribution to rising sea levels. 72 “It’s methane” Methane plays a minor role in global warming but could get much worse if permafrost starts to melt. While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere. Hence the amount of warming methane contributes is 28% of the warming CO2 contributes. 73 “CO2 has a short residence time” Excess CO2 from human emissions has a long residence time of over 100 years Individual carbon dioxide molecules have a short life time of around 5 years in the atmosphere. However, when they leave the atmosphere, they’re simply swapping places with carbon dioxide in the ocean. The final amount of extra CO2 that remains in the atmosphere stays there on a time scale of centuries. 74 “CO2 measurements are suspect” CO2 levels are measured by hundreds of stations across the globe, all reporting the same trend. CO2 levels are measured by hundreds of stations scattered across 66 countries which all report the same rising trend. 75 “Humidity is falling” Multiple lines of independent evidence indicate humidity is rising and provides positive feedback. To claim that humidity is decreasing requires you ignore a multitude of independent reanalyses that all show increasing humidity. It requires you accept a flawed reanalysis that even its own authors express caution about. It fails to explain how we can have short-term positive feedback and long-term negative feedback. In short, to insist that humidity is decreasing is to neglect the full body of evidence. 76 “500 scientists refute the consensus” Around 97% of climate experts agree that humans are causing global warming. Close inspection of the studies alleged to refute man-made global warming finds that many of these papers do no such thing. Of the few studies that do claim to refute man-made global warming, these repeat well debunked myths. 77 “Neptune is warming” And the sun is cooling. Neptune’s orbit is 164 years so observations (1950 to present day) span less than a third of a Neptunian year. Climate modelling of Neptune suggests its brightening is a seasonal response. Eg – Neptune’s southern hemisphere is heading into summer. 78 “Springs aren’t advancing” Hundreds of flowers across the UK are flowering earlier now than any time in 250 years. A synthesis of nearly 400,000 first flowering records covering 405 species across the UK found that British plants are flowering earlier now than at any time in the last 250 years. 79 “Jupiter is warming” Jupiter is not warming, and anyway the sun is cooling. Jupiter’s climate change is due to shifts in internal turbulence fueled from an internal heat source – the planet radiates twice as much energy as it receives from the sun. 80 “It’s land use” Land use plays a minor role in climate change, although carbon sequestration may help to mitigate. Correlations between warming and economic activity are most likely spurious. They don’t take into account local forcing agents such as tropospheric ozone or black carbon. Correlations are likely over-estimated since grid boxes in both economic and climate data are not independent. Lastly, there is significant independent evidence for warming in the oceans, snow cover and sea ice extent changes. 81 “Scientists tried to ‘hide the decline’ in global temperature” The ‘decline’ refers to a decline in northern tree-rings, not global temperature, and is openly discussed in papers and the IPCC reports. ‘Mike’s Nature trick’ refers to the technique of plotting recent instrumental data along with the reconstructed data. This places recent global warming trends in the context of temperature changes over longer time scales. “Hide the decline” refers to a decline in the reliability of tree rings to reflect temperatures after 1960. This is known as the ‘divergence problem’ where tree ring proxies diverge from modern instrumental temperature records after 1960, discussed in the peer reviewed literature as early as 1995. 82 “CO2 is not increasing” CO2 is increasing rapidly, and is reaching levels not seen on the earth for millions of years. Currently, humans are emitting around 29 billion tonnes of carbon dioxide into the atmosphere per year. Around 43% remains in the atmosphere – this is called the ‘airborne fraction’. The rest is absorbed by vegetation and the oceans. While there are questions over how much the airborne fraction is increasing, it is clear that the total amount of CO2 in the atmosphere is increasing dramatically. Current CO2 levels are the highest in 15 million years. 83 “Record snowfall disproves global warming” Warming leads to increased evaporation and precipitation, which falls as increased snow in winter. To claim that record snowfall is inconsistent with a warming world betrays a lack of understanding of the link between global warming and extreme precipitation. Warming causes more moisture in the air which leads to more extreme precipitation events. This includes more heavy snowstorms in regions where snowfall conditions are favourable. Far from contradicting global warming, record snowfall is predicted by climate models and consistent with our expectation of more extreme precipitation events. 84 “They changed the name from global warming to climate change” ‘Global warming’ and ‘climate change’ mean different things and have both been used for decades. There have long been claims that some unspecificed “they” has “changed the name from ‘global warming’ to ‘climate change’”. In reality, the two terms mean different things, have both been used for decades, and the only individual to have specifically advocated changing the name in this fashion is a global warming ‘skeptic’. 85 “Solar Cycle Length proves its the sun” The sun has not warmed since 1970 and so cannot be driving global warming. The claim that solar cycle length proves the sun is driving global warming is based on a single study published in 1991. Subsequent research, including a paper by a co-author of the original 1991 paper, finds the opposite conclusion. Solar cycle length as a proxy for solar activity tells us the sun has had very little contribution to global warming since 1975. 86 “CO2 is coming from the ocean” The ocean is absorbing massive amounts of CO2, and is becoming more acidic as a result. Measurements of carbon isotopes and falling oxygen in the atmosphere show that rising carbon dioxide is due to the burning of fossil fuels and cannot be coming from the ocean. 87 “IPCC overestimate temperature rise” Monckton used the IPCC equation in an inappropriate manner. Lord Monckton has taken a single equation from the IPCC, used it in an inappropriate manner, and then attributed his results to the IPCC. This is as if I borrowed your car, drove into a tree, and then blamed you. He uses a method that is clearly intended to examine the long-term response of temperature to changes in carbon dioxide, and which is never used by the IPCC (nor should it be) to make predictions about current temperature trends. A slight change in Lord Monckton’s methodology as of July 2010 still does not make his method or attribution remotely appropriate. 88 “CO2 is not the only driver of climate” Theory, models and direct measurement confirm CO2 is currently the main driver of climate change. While there are many drivers of climate, CO2 is the most dominant radiative forcing and is increasing faster than any other forcing. 89 “Peer review process was corrupted” An Independent Review concluded that CRU’s actions were normal and didn’t threaten the integrity of peer review. The Independent Climate Change Email Review investigated the CRU scientists’ actions relating to peer review. In one case, it judged their strong reaction to a controversial paper was not unusual. In another, it turned out the alleged victim had actually been spreading malicious rumours about CRU. In a third, the allegation of collusion fell apart when the full email exchange was examined. The Review concluded that CRU’s actions were normal and did not threaten the integrity of peer review. 90 “Southern sea ice is increasing” Antarctic sea ice has grown in recent decades despite the Southern Ocean warming at the same time. Antarctic sea ice has growing over the last few decades but it certainly is not due to cooling – the Southern Ocean has shown warming over same period. Increasing southern sea ice is due to a combination of complex phenomena including cyclonic winds around Antarctica and changes in ocean circulation. 91 “It’s microsite influences” Microsite influences on temperature changes are minimal; good and bad sites show the same trend. Poor weather stations actually show a cooler trend compared to well sited stations. This is due to instrumentation changes. When this is taken into account, there’s negligible difference between poor and well sited stations. 92 “Phil Jones says no global warming since 1995″ Phil Jones was misquoted. When you read Phil Jones’ actual words, you see he’s saying thereis a warming trend but it’s not statistically significant. He’s not talking about whether warming is actually happening. He’s discussing our ability to detect that warming trend in a noisy signal over a short period. 93 “Humans are too insignificant to affect global climate” Humans are small but powerful, and human CO2 emissions are causing global warming. Atmospheric CO2 levels are rising by 15 gigatonnes per year. Humans are emitting 26 gigatonnes of CO2 into the atmosphere. Humans are dramatically altering the composition of our climate. 94 “Lindzen and Choi find low climate sensitivity” Lindzen and Choi’s paper is viewed as unacceptably flawed by other climate scientists. Lindzen’s analysis has several flaws, such as only looking at data in the tropics. A number of independent studies using near-global satellite data find positive feedback and high climate sensitivity. 95 “Dropped stations introduce warming bias” If the dropped stations had been kept, the temperature would actually be slightly higher. Dropped weather stations actually show a slightly warmer trend compared to kept stations. So the removal of these faster warming dropped stations has actually imposed a slight cooling trend although the difference is negligible since 1970. 96 “It’s too hard” Scientific studies have determined that current technology is sufficient to reduce greenhouse gas emissions enough to avoid dangerous climate change. The argument that solving the global warming problem by reducing human greenhouse gas emissions is “too hard” generally stems from the belief that (i) our technology is not sufficiently advanced to achieve significant emissions reductions, and/or (ii) that doing so would cripple the global economy. However, studies have determined that current technology is sufficient to reduce greenhouse gas emissions the necessary amount, and that we can do so without significant impact on the economy. 97 “It’s albedo” Albedo change in the Arctic, due to receding ice, is increasing global warming. The long term trend from albedo is that of cooling. In recent years, satellite measurements of albedo show little to no trend. 98 “Tree-rings diverge from temperature after 1960″ This is a detail that is complex, local, and irrelevant to the observed global warming trend. The divergence problem is a physical phenomenon – tree growth has slowed or declined in the last few decades, mostly in high northern latitudes. The divergence problem is unprecedented, unique to the last few decades, indicating its cause may be anthropogenic. The cause is likely to be a combination of local and global factors such as warming-induced drought and global dimming. Tree-ring proxy reconstructions are reliable before 1960, tracking closely with the instrumental record and other independent proxies. 99 “Hansen’s 1988 prediction was wrong” Jim Hansen had several possible scenarios; his mid-level scenario B was right. Subsequent comparison of observations with predictions find that Hansen’s Scenario B (which most closely matched the level of CO2 emissions) shows close correlation with observed temperatures.
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