copenlu/druid huggingface dataset:
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2022-10-12): We know this warming is largely caused by human activities because the key role that carbon dioxide plays in maintaining Earth’s natural greenhouse effect has been understood since the mid-1800s. Unless it is offset by some equally large cooling influence, more atmospheric carbon dioxide will lead to warmer surface temperatures. Since 1800, the amount of carbon dioxide in the atmosphere has increased from about 280 parts per million to 410 ppm in 2019. We know from both its rapid increase and its isotopic "fingerprint" that the source of this new carbon dioxide is fossil fuels, and not natural sources like forest fires, volcanoes, or outgassing from the ocean. Finally, no other known climate influences have changed enough to account for the observed warming trend. Taken together, these and other lines of evidence point squarely to human activities as the cause of recent global warming.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2022-06-15): - While the Sun has played a role in past climate changes, the evidence shows the current warming cannot be explained by the Sun. [...] But several lines of evidence show that current global warming cannot be explained by changes in energy from the Sun: [...] - If a more active Sun caused the warming, scientists would expect warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere and a warming at the surface and lower parts of the atmosphere. That's because greenhouse gases are slowing heat loss from the lower atmosphere.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2024-09-25): Recent News global warming, the phenomenon of increasing average air temperatures near the surface of Earth over the past one to two centuries. Climate scientists have since the mid-20th century gathered detailed observations of various weather phenomena (such as temperatures, precipitation, and storms) and of related influences on climate (such as ocean currents and the atmosphere’s chemical composition). These data indicate that Earth’s climate has changed over almost every conceivable timescale since the beginning of geologic time and that human activities since at least the beginning of the Industrial Revolution have a growing influence over the pace and extent of present-day climate change. Giving voice to a growing conviction of most of the scientific community, the Intergovernmental Panel on Climate Change (IPCC) was formed in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP). The IPCC’s Sixth Assessment Report (AR6), published in 2021, noted that the best estimate of the increase in global average surface temperature between 1850 and 2019 was 1.07 °C (1.9 °F). An IPCC special report produced in 2018 noted that human beings and their activities have been responsible for a worldwide average temperature increase between 0.8 and 1.2 °C (1.4 and 2.2 °F) since preindustrial times, and most of the warming over the second half of the 20th century could be attributed to human activities.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2024-01-01): Scientists have determined that, when all human and natural factors are considered, Earth’s climate balance has been altered towards warming, with the biggest contributor being increases in CO2. [...] Rigorous analysis of all data and lines of evidence shows that most of the observed global warming over the past 50 years or so cannot be explained by natural causes and instead requires a significant role for the influence of human activities. [...] Fingerprinting is a powerful way of studying the causes of climate change. Different influences on climate lead to different patterns seen in climate records. This becomes obvious when scientists probe beyond changes in the average temperature of the planet and look more closely at geographical and temporal patterns of climate change. For example, an increase in the Sun’s energy output will lead to a very different pattern of temperature change (across Earth’s surface and vertically in the atmosphere) compared to that induced by an increase in CO2 concentration. Observed atmospheric temperature changes show a fingerprint much closer to that of a long-term CO2 increase than to that of a fluctuating Sun alone. Scientists routinely test whether purely natural changes in the Sun, volcanic activity, or internal climate variability could plausibly explain the patterns of change they have observed in many different aspects of the climate system. These analyses have shown that the observed climate changes of the past several decades cannot be explained just by natural factors.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2022-06-15): With that said, multiple studies published in peer-reviewed scientific journals1 show that climate-warming trends over the past century are extremely likely due to human activities. In addition, most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources. [...] American Geophysical Union "Based on extensive scientific evidence, it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century. There is no alterative explanation supported by convincing evidence." (2019)5 [...] International Academies: Joint Statement "Climate change is real. There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)." (2005, 11 international science academies)10
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2024-02-14): Climate change encompasses not only rising average temperatures but also natural disasters, shifting wildlife habitats, rising seas, and a range of other impacts. All of these changes are emerging as humans continue to add heat-trapping greenhouse gases, like carbon dioxide and methane, to the atmosphere. [...] Restoring nature may also help limit warming. Trees, oceans, wetlands, and other ecosystems help absorb excess carbon—but when they're lost, so too is their potential to fight climate change.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2024-10-08): Compounding the problem is the recent decline in atmospheric aerosols from efforts to cut pollution. These small particles suspended in the air come from both natural and human processes, and have helped cool the planet. Without this cooling effect, the pace of global warming may accelerate. We don’t know for sure because aerosol properties are not yet measured well enough. Other environmental issues are now feeding into climate change. Deforestation in critical areas such as the Amazon is reducing the planet’s capacity to absorb carbon naturally, driving additional warming. This creates a feedback loop, where warming causes trees to die which in turn amplifies global temperatures. [...] Climate change is already here. But it could get much, much worse. By slashing emissions, boosting natural climate solutions and working towards climate justice, the global community can still fend off the worst version of our future.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2021-10-25): They reveal there would have been little global warming - and possibly some cooling - over the 20th and 21st Centuries, if only natural factors had been influencing the climate. [...] These fluctuations between hot and cold have been caused by a variety of phenomena, including the way the Earth wobbles as it orbits the Sun over long periods, volcanic eruptions and short-term climate cycles such as El Niño.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2023-03-20): 1. Human-induced global warming of 1.1 degrees C has spurred changes to the Earth’s climate that are unprecedented in recent human history. [...] Additional warming will increase the magnitude of these changes. Every 0.5 degree C (0.9 degrees F) of global temperature rise, for example, will cause clearly discernible increases in the frequency and severity of heat extremes, heavy rainfall events and regional droughts. Similarly, heatwaves that, on average, arose once every 10 years in a climate with little human influence will likely occur 4.1 times more frequently with 1.5 degrees C (2.7 degrees F) of warming, 5.6 times with 2 degrees C (3.6 degrees F) and 9.4 times with 4 degrees C (7.2 degrees F) — and the intensity of these heatwaves will also increase by 1.9 degrees C (3.4 degrees F), 2.6 degrees C (4.7 degrees F) and 5.1 degrees C (9.2 degrees F) respectively.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2023-11-18): During an El Niño, warmer surface waters in the eastern Pacific release additional heat into the atmosphere. This typically leads to a surge in global air temperatures. [...] The ongoing 2023 El Niño may be releasing even more warmth than previous ones, because the world had previously been in an extended cool phase - an opposite weather system known as La Niña. [...] They suggest that the climate is yet to fully respond to the greenhouse gases already emitted. One reason could be the artificial cooling effect of aerosols. This leaves more warming "in the pipeline" than previously thought, they argue.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2023-09-25): With that said, multiple studies published in peer-reviewed scientific journals1 show that climate-warming trends over the past century are extremely likely due to human activities. In addition, most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources. [...] American Meteorological Society "Research has found a human influence on the climate of the past several decades ... The IPCC (2013), USGCRP (2017), and USGCRP (2018) indicate that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-twentieth century." (2019)7 - [...] International Academies: Joint Statement "Climate change is real. There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)." (2005, 11 international science academies)10 -
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2024-04-22): Important natural factors include El Niño and the Hunga Tonga eruption. The Hunga Tonga–Hunga Ha’apai eruption in 2022 has been suggested to explain some of the 2023 extreme warmth. Unlike more common sulfur-rich volcanic eruptions, the Hunga Tonga eruption injected large amounts of water vapour into the stratosphere and thereby could enhance tropospheric warming5. However, its net contribution to global temperature remains to be determined, including careful consideration of the associated aerosol responses6. [...] Overall, about 42% of the globe experienced heat (defined as more than two standard deviations) in 2023, surpassing the 2016 record of about 32% by a large margin (Fig. 1c). Extreme heat (defined as three standard deviations exceedance) occupied about 13% of the global surface in 2023, almost doubling the 2016 area of about 7%. Area fractions measured for global land or ocean only exhibit similar percentages to the global results (not shown), indicating the strong land-ocean connection. Although individual basin surface temperatures will be affected by region-specific natural variabilities such as the Atlantic Multidecadal Variability for the North Atlantic12, strong warming over most of the global ocean basins would not occur in the same year without systematic large-scale influences.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2022-06-15): The current warming trend is different because it is clearly the result of human activities since the mid-1800s, and is proceeding at a rate not seen over many recent millennia.1 It is undeniable that human activities have produced the atmospheric gases that have trapped more of the Sun’s energy in the Earth system. This extra energy has warmed the atmosphere, ocean, and land, and widespread and rapid changes in the atmosphere, ocean, cryosphere, and biosphere have occurred. [...] The planet's average surface temperature has risen about 2 degrees Fahrenheit (1 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide emissions into the atmosphere and other human activities.4 Most of the warming occurred in the past 40 years, with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the warmest year on record.5 [...] B.D. Santer et al., "Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes." Science 301 (25 July 2003): 479-483. https://doi.org/10.1126/science.1084123.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2020-01-29): Air temperatures on Earth have been rising since the Industrial Revolution. While natural variability plays some part, the preponderance of evidence indicates that human activities—particularly emissions of heat-trapping greenhouse gases—are mostly responsible for making our planet warmer. According to an ongoing temperature analysis led by scientists at NASA’s Goddard Institute for Space Studies (GISS), the average global temperature on Earth has increased by at least 1.1° Celsius (1.9° Fahrenheit) since 1880. The majority of the warming has occurred since 1975, at a rate of roughly 0.15 to 0.20°C per decade. [...] The leveling off of temperatures in the middle of the 20th century can be explained by natural variability and by the cooling effects of aerosols generated by factories, power plants, and motor vehicles in the years of rapid economic growth after World War II. Fossil fuel use also increased after the war (5 percent per year), boosting greenhouse gases. Cooling from aerosol pollution happened rapidly. In contrast, greenhouse gases accumulated slowly, but they remain in the atmosphere for a much longer time. According to former GISS director James Hansen, the strong warming trend of the past four decades likely reflects a shift from balanced aerosol and greenhouse gas effects on the atmosphere to a predominance of greenhouse gas effects after aerosols were curbed by pollution controls.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2021-08-09): The report shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming since 1850-1900, and finds that averaged over the next 20 years, global temperature is expected to reach or exceed 1.5°C of warming. This assessment is based on improved observational datasets to assess historical warming, as well progress in scientific understanding of the response of the climate system to human-caused greenhouse gas emissions.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2022-09-01): The rise is mostly due to thermal expansion of the oceans because of warming. But melting ice from glaciers and the Antarctic ice sheet is also contributing. It is predicted that Europe will experience an average 60 to 80 cm sea-level rise by the end of the century, mainly depending on the rate at which the Antarctic ice sheet melts. [...] The increase in temperature is particularly significant in many mountain regions, where loss of glacier mass, reduced snow cover, thawing of permafrost and changing precipitation patterns, including less precipitation falling as snow, have been observed and are expected to increase further. This could lead to an increase in the frequency and intensity of floods in some mountain areas (e.g. in parts of Scandinavia) that can impact people and the built environment. Additional projected impacts include reduced winter tourism, lower energy potential from hydropower in southern Europe, a shift in vegetation zones and extensive biodiversity loss. Plant and animal species living close to mountain tops face the risk of becoming extinct due to the inability to migrate to higher regions.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2020-10-12): Each of the following selected projections are from the IPCC special report. In most instances, climate-related risks for natural and human systems were found to be higher, often significantly so, under the hotter temperature threshold. The degree of these risks depends on many factors, such as the rate, duration and magnitude of warming; geographic location; levels of development and vulnerability; and on how humans respond through adaptation and mitigation options. Some regions, such as small island states, will experience multiple climate-related risks that compound upon each other. [...] The impacts of climate change haven’t been spread evenly around our planet and they won’t be in the future, either. Temperatures increase at different speeds everywhere, with warming generally higher over land areas than oceans. The strongest warming is happening in the Arctic during its cool seasons, and in Earth’s mid-latitude regions during the warm season. In many regions, warming has already surpassed 1.5 degrees Celsius above pre-industrial levels. More than one-fifth of all humans live in regions that have already seen warming greater than 1.5 degrees Celsius in at least one season. Climate-related risks were found to be generally higher at lower latitudes and for disadvantaged people and communities.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2022-05-09): Past changes in Earth’s temperature happened very slowly, over hundreds of thousands of years. However, the recent warming trend is happening much faster than it ever has. Natural cycles of warming and cooling are not enough to explain the amount of warming we have experienced in such a short time—only human activities can account for it. Scientists worry that the climate is changing faster than some living things can adapt to it. [...] According to the IPCC’s most recent report (in 2007), Earth’s average surface temperatures have risen about 0.74 degrees Celsius (1.33 degrees Fahrenheit) during the past 100 years. The increase is greater in northern latitudes. The IPCC also found that land regions are warming faster than oceans. The IPCC states that most of the temperature increase since the mid-20th century is likely due to human activities. Human activities contribute to global warming by increasing the greenhouse effect. The greenhouse effect happens when certain gases—known as greenhouse gases—collect in Earth’s atmosphere. These gases, which occur naturally in the atmosphere, include carbon dioxide, methane, nitrogen oxide, and fluorinated gases sometimes known as chlorofluorocarbons (CFCs).
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2024-07-17): In 2017, The Nature Conservancy led a landmark study that showed how natural climate solutions to protect, better manage, and restore forests, grasslands and wetlands could contribute a third of the emissions reductions we need to avoid the worst impacts of climate change. The authors developed a framework to distill the evidence into natural climate solutions pathways that demonstrate the full climate potential of nature.
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2011-03-03): The global climate has changed relative to the pre-industrial period, and there are multiple lines of evidence that these changes have had impacts on organisms and ecosystems, as well as on human systems and well-being (high confidence). The increase in global mean surface temperature (GMST), which reached 0.87°C in 2006–2015 relative to 1850–1900, has increased the frequency and magnitude of impacts (high confidence), strengthening evidence of how an increase in GMST of 1.5°C or more could impact natural and human systems (1.5°C versus 2°C). {3.3, 3.4, 3.5, 3.6, Cross-Chapter Boxes 6, 7 and 8 in this chapter} Human-induced global warming has already caused multiple observed changes in the climate system (high confidence). Changes include increases in both land and ocean temperatures, as well as more frequent heatwaves in most land regions (high confidence). There is also (high confidence) global warming has resulted in an increase in the frequency and duration of marine heatwaves. Further, there is substantial evidence that human-induced global warming has led to an increase in the frequency, intensity and/or amount of heavy precipitation events at the global scale (medium confidence), as well as an increased risk of drought in the Mediterranean region (medium confidence). {3.3.1, 3.3.2, 3.3.3, 3.3.4, Box 3.4}
Claim: Most of the recent warming could be natural (Jennifer Marohasy, 2017-07-09)
Evidence (2010-06-03): In Earth’s history before the Industrial Revolution, Earth’s climate changed due to natural causes not related to human activity. Most often, global climate has changed because of variations in sunlight. Tiny wobbles in Earth’s orbit altered when and where sunlight falls on Earth’s surface. Variations in the Sun itself have alternately increased and decreased the amount of solar energy reaching Earth. Volcanic eruptions have generated particles that reflect sunlight, brightening the planet and cooling the climate. Volcanic activity has also, in the deep past, increased greenhouse gases over millions of years, contributing to episodes of global warming. [...] These natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades. We know this because scientists closely monitor the natural and human activities that influence climate with a fleet of satellites and surface instruments. [...] Though people have had the largest impact on our climate since 1950, natural changes to Earth’s climate have also occurred in recent times. For example, two major volcanic eruptions, El Chichon in 1982 and Pinatubo in 1991, pumped sulfur dioxide gas high into the atmosphere. The gas was converted into tiny particles that lingered for more than a year, reflecting sunlight and shading Earth’s surface. Temperatures across the globe dipped for two to three years.