"The environmental changes related to human influences on climate since 1970 have increased SSTs and water vapor, and the results suggest how this may have altered hurricanes and increased associated storm rainfalls, with the latter quantified to date to be of order 6 to 8%"

"While we can provide evidence that the risk of hot and dry conditions has increased, we cannot say that the 2011 Texas drought and heat wave was "extremely unlikely" (in any absolute sense) to have occurred before this recent warming."

"In none of the four regions defined in this study [where the contiguoug US is divided into four] is there strong statistical evidence for flood magnitudes increasing with increasing GMCO2 [global mean CO2 concentration]."

"Our analyses of the CMIP5 global climate model ensemble suggest that the likelihood of extreme July temperature anomalies is greater in the current forcing than in the preindustrial forcing."

"The anthropogenic contribution to the extreme seasonal (MAM) warmth over the eastern United States can be estimated as about 35%, or in terms of risk, anthropogenic forcing leads to a factor of 12 increase in the risk of such an event according to our calculations."

"The contribution of potential changes in circulation to the recent long-term warming in the United States, therefore, requires further research."

"Quantitative attribution of the overall human-induced contribution since preindustrial times is complicated by the lack of a detected century-scale temperature trend over Texas."

"It is concluded that the extreme Great Plains drought did not require extreme external forcings and could plausibly have arisen from atmospheric noise alone."

"The implication is that human alteration of the atmospheric composition may have had little effect on the frequency of low-precipitation periods."

"Accordingly, we estimate that relative sea level over 1950–2012 from global SLR (thermal expansion and ice melt), VLM (subsidence), and ocean circulation variability has contributed to a one- to two-thirds decrease in Sandy-level event recurrences."

"Surge simulations suggest that flood elevations would have been 15 to 60 % lower c. 1900 than the conditions observed in 2005. This drastic change suggests that significantly more flood damage occurred in 2005 than would have occurred if sea level and climate conditions had been like those c. 1900."

"It was suggested that both the anthropogenic warming and an atmospheric circulation regime related to the natural variability of SST and SIC made the heat wave event more likely."

"There is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013–2014 and the associated drought."

"California’s driest 12-month period on record occurred during 2013/14, and although global warming has very likely increased the probability of certain large-scale atmospheric conditions, implications for extremely low precipitation in California remain uncertain."

"The 2013 SST anomalies produced a predilection for California drought, whereas the long-term warming trend appears to make no appreciable contribution because of the counteraction between its dynamical and thermodynamic effects."

"Long-term SST warming trends did not contribute substantially to the 2012/13 and 2013/14 California droughts. North Pacific SSTs were exceptionally warm, however, and coupled models indicate more frequent extreme precipitation."

"The Coupled Model Intercomparison Project phase 5 model analyses suggest that seasonal and annual mean precipitation extremes occurring during 2013 in north-central and eastern U.S. regions, while primarily attributable to intrinsic variability, were also partly attributable to anthropogenic and natural forcings combined."

"The probability for an extreme five-day September rainfall event over northeast Colorado, as was observed in early September 2013, has likely decreased due to climate change."

"An early October blizzard in South Dakota is determined to be climatologically anomalous. Climate models suggest that early autumn extreme snowfall events in western South Dakota are less likely due to anthropogenic climate change."

"This study shows that although low precipitation was the main driver of the WY 2014 drought conditions in California, temperature played an important role in exacerbating the drought."

"We therefore conclude that anthropogenic warming is increasing the probability of co-occurring warm–dry conditions like those that have created the acute human and ecosystem impacts associated with the 'exceptional' 2012–2014 drought in California."

"[A] long-term warming trend likely contributed to surface moisture deficits during the drought. As such, the precipitation deficit during the drought was dominated by natural variability."

"Although natural variability dominates, anthropogenic warming has substantially increased the overall likelihood of extreme California droughts."

"The results thus indicate that the net effect of climate change has made agricultural drought less likely and that the current severe impacts of drought on California’s agriculture have not been substantially caused by long-term climate changes."

"Anthropogenic global warming contributed to the physical processes that caused the persistent precipitation in May 2015."

"The frigid 2013/14 Midwestern winter was 20–100 times less likely than in the 1880s due to long-term warming, while winter temperature variability has shown little long-term change."

"The near-record number of extremely cold days during winter 2014 in the eastern United States cannot be attributed to trends or variability changes. Daily temperature variability is actually decreasing, in contrast to CMIP5 simulations and projections."

"New climate simulations suggest that the extremely active 2014 Hawaiian hurricane season was made substantially more likely by anthropogenic forcing, but that natural variability of El Niño was also partially involved."

"The fire season in northern California during 2014 was the second largest in terms of burned areas since 1996. An increase in fire risk in California is attributable to human-induced climate change."

"[B]oth human influence and sea surface temperature (SST) anomalies contributed strongly to the risk of snow drought in Oregon and Washington: the contribution of SST anomalies was about twice that of human influence."

"The 2014/15 snowpack drought resulted from exceedingly high temperatures notwithstanding normal precipitation—a drought type that may reoccur due to accelerated anthropogenic warming and aggravated by naturally driven low precipitation."

"[W]e deduce an increase in the likelihood of extreme one-day precipitation but of a smaller magnitude than what would be expected in a warming world according to the Clausius–Clapeyron relation. For five-day extremes, we are unable to detect a change in likelihood."

"These simulations suggest that ~20% of the 4 day precipitation that fell on Louisiana (average of detrend and double trend) could have been augmented by climate warming trends."

"Consistent with observations, the majority of climate models find that climate change has led to a shift in the distribution of winter daily minimum temperatures toward warmer conditions, and subsequently a decrease in the likelihood of extreme cold waves in the North Atlantic."

"The cold air outbreak of the next few days is nothing unusual, and neither inconsistent with an overall picture of a warming world, nor evidence that global warming is making cold weather more extreme."

"There is no systematic trend in the number of extremely cold days, thus no evidence to suggest that the frequency or persistence of cold events is systematically changing"

"Due to the effect of sea level rise, the return period of Hurricane Sandy’s flood height decreased by a factor of ∼3× from year 1800 to 2000 and is estimated to decrease by a further ∼4.4× from 2000 to 2100 under a moderate-emissions pathway."

"The 2015 Alaska fire season burned the second largest number of acres since records began in 1940. Human-induced climate change may have increased the risk of a fire season of this severity by 34%–60%."

"We estimate that human-caused climate change contributed to an additional 4.2 million ha of forest fire area during 1984–2015, nearly doubling the forest fire area expected in its absence."

"Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model."

"The probability of a 0.57-m tidal flood within the Miami region has increased by >500% since 1994 from a 10.9-cm sea level rise (SLR)-related trend in monthly highest tides."

"Overall, we find that the chances of seeing a February as warm as the one experienced across the Lower 48 has increased more than threefold because of human-caused climate change."

"An anthropogenic impact on precipitation was detectable in the simulations, doubling the likelihood of what would have been a rainfall deficit with a 2% exceedance probability under preindustrial-level forcings."

"These results allow a tenuous case for human-driven climate change driving increased gradients and favoring the west coast ridge, but observational data are not sufficiently accurate to confirm or reject this case."

"Taking into account all modeling results, the probability of an event like the one in south Louisiana in 2016 has increased at least by a factor of 1.4 due to radiative forcing."

"Using this ‘conditional event attribution’ approach we find that our regional climate model simulations indicate that anthropogenic drivers increased the magnitude of heavy northeast Colorado rainfall for the wet week in September 2013 by 30%, with the occurrence probability of a week at least that wet increasing by at least a factor of 1.3."

"Anthropogenic warming reduced average snowpack levels by 25%, with middle‐to‐low elevations experiencing reductions between 26 and 43%"

"Extrapolating these results to the 2017 event, we conclude that global warming made the precipitation about 15% (8%–19%) more intense, or equivalently made such an event three (1.5–5) times more likely."

"However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared with preindustrial or modern flood heights"

"[W]e found that recent warming of 0.9°C has likely already reduced river flows from −2.7% to −9% from the mean 1906–1999 flow. This represents approximately one‐sixth to one‐half (average of one‐third) of the total flow loss during the 2000–2014 drought."

"Anthropogenic forcing made the occurrence of observed 2017 northern Great Plains drought intensity up to 1.5 times more likely through aridification due to long-term increases in evapotranspiration over precipitation."

"The 2017 northern High Plains precipitation deficits were largely the result of internal atmospheric variability. Global warming may have exacerbated the dry condition by producing surface warming and increasing the probability of heat waves there."

"A regime change in El Nino-Southern Oscillation-related precipitation anomalies appears to have occurred, from being negatively correlated before 1950 to positive and significantly correlated after 1970, suggesting a likely effect of anthropogenic warming on the December 2015 extreme precipitation event."

"Failure of heavy rain in Southern California during the 2016 strong El Niño compared to flooding rains during the 1983 strong El Niño does not constitute a climate change effect."

"Results show that historical warming reduced 2016–2017 Sierra Nevada snow water equivalent by 20% while increasing early‐season runoff by 30%."

"Model simulations indicate that anthropogenic climate change has made extreme snowstorms less likely over the mid-Atlantic United States. Empirical evidence shows no decline since 1901, with recent storms colder than before."

"Cold outbreaks like this are getting warmer (less frequent) due to global warming, but cold waves still occur somewhere in North America almost every winter."

"Accordingly, record high ocean heat values not only increased the fuel available to sustain and intensify Harvey but also increased its flooding rains on land. Harvey could not have produced so much rain without human‐induced climate change."

"The 60 member ensemble simulations suggest that post-1980 climate warming could have contributed to the extreme precipitation that fell on southeast Texas during 26–29 August 2017 by approximately 20%, with an interquartile range of 13%–37%."

"Significant impacts on California Current living marine resources in 2016 resulted from sustained extremely high ocean temperatures forced by a confluence of natural drivers and likely exacerbated by anthropogenic warming."

"The 2016 Alaska marine heat wave was unprecedented in terms of sea surface temperatures and ocean heat content, and CMIP5 data suggest human-induced climate change has greatly increased the risk of such anomalies."

"We report a discernable, potentially pronounced subseasonal change in the MP [mid-tropospheric perturbations] climatology associated with the changing climate of North America."

"The evidence is strong that the probability of an extreme heatwave is much greater with anthropogenic influence than without…[and for drought] we see evidence for a RR [risk ratio] greater than one, with our best estimate of a RR of about two at a variety of event definitions."

"Human-induced (HI) warming increased Four Corners’ vapor pressure deficits and reduced the Normalized Difference Vegetation Index by ~18%–30%. Without HI warming, March snow water equivalent would have been ~20% higher'

"We find that anthropogenic warming leads to enhanced soil moisture–temperature coupling in water-limited areas of the southern Great Plains and/or southwestern United States and consequently amplifies the intensity of extreme heat waves during severe droughts."

"Exceptional January–September total precipitation contributed to flooding across the mid-Atlantic United States from May to September 2018, and was made 1.1 to 2.3 times more likely by anthropogenic climate change."

"We conclude that two-day extreme precipitation events along the Gulf Coast as intense as observed on 19–20 September 2019 or higher have become 1.6 to 2.6 times more likely due to anthropogenic climate change, or 9% to 17% more intense."

"Our data reveal an emergent positive trend in damage, which we attribute to a detectable change in extreme storms due to global warming."

"During 1972–2018, California experienced a fivefold increase in annual burned area, mainly due to more than an eightfold increase in summer forest‐fire extent. Increased summer forest‐fire area very likely occurred due to increased atmospheric aridity caused by warming."

"We use a large-ensemble regional modelling framework to show that GHG increases caused slightly enhanced heatwave activity over the eastern United States during 1934 and 1936."

"Compared to the baseline scenario with the external forcing removed, this event was ∼1.28-fold larger in flood extent, an approximate 3.4-time larger in the number of affected buildings, and an estimated 5.8- and 7.1-time larger in structural and content damage, respectively."

"The extreme rainfall was increased by up to 10%, and the fraction of rainfall accumulations of more than 30 inches was increased by more than 7% of what it would have been without climate change." & "The maximum size of Hurricane Florence [was] about 9 km larger in mean maximum diameter (or a 1.6% increase in storm area) due to climate change."

"We find an increase in the climate model-estimated probability of these extreme autumn conditions since ~1950, including a long-term trend toward increased same-season co-occurrence of extreme fire weather conditions in northern and southern California."

"If we set temperature every year to its climatology, the model yields a discharge trend [for 1913-2017] of −8.4%/century and a discharge deficit [for 2000-17] of −8.1%. We conclude that temperature sensitivity accounts for more than half of both drying phenomena, consistent with a previous analysis."

"With an average estimate of damages from Harvey assessed at about US$90bn, applying this fraction [of attributable risk] gives a best estimate of US$67bn, with a likely lower bound of at least US$30bn, of these damages that are attributable to the human influence on climate."

"The 1996 shift in Northeast EP can be attributed to both climate variability (especially AMV) and anthropogenic forcings (especially GHG), rather than either factor alone."

"Two snow-induced floods (the Red in 2011 and Missouri in 2011) were suppressed [by climate change], despite the increased precipitation, may be due to decreased snow and earlier snowmelt peaks due to warming."

"Two snow-induced floods (the Red in 2011 and Missouri in 2011) were suppressed [by climate change], despite the increased precipitation, may be due to decreased snow and earlier snowmelt peaks due to warming."

"[O]ngoing climate change affected the occurrence of 64% (14 of 22) of historical floods from 2010 to 2013; they were enhanced in eight basins and suppressed in six."

"CMIP6 results find nonsignificant dynamical effects of anthropogenic climate change on such regional winds; thermodynamic effects alone decreased the probability of this cold event by 70%."

"The cost of Hurricane Harvey attributable to anthropogenic global warming as $13bn dollars."

Results indicate "a threefold increased risk of Alaska’s extreme fires during recent decades due to primarily anthropogenic ignition and secondarily climate-induced biofuel abundance."

"Both estimates [68% from observations and 88% from models] suggest that anthropogenic warming is the main cause for increasing fire weather and provide a likely range for the true anthropogenic contribution to the western US trend in vapour pressure deficit."

"During August 2020, when the August Complex “Gigafire” occurred in the western US, anthropogenic warming likely explains 50% of the unprecedented high vapour pressure deficit anomalies."

The "analysis suggests that the anthropogenic signal of increased fire risk had not yet emerged in 2019 because of the [model]’s internal variability."

"Anthropogenic climate change has increased the probability of extreme Susquehanna River mean streamflows."

"[W]e estimate that county-level temperature trends have contributed $27.0bn – or 19% – of the national-level crop insurance losses over the 1991–2017 period."

"We find that approximately $8.1bn of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise"

"About 3 out of 20 heat-realteed illness visits are attributable to anthropogenic climate change in Coastal and Piedmont regions."

"The multimodel mean anthropogenic climate change trends account for 42% of the southwestern North America soil moisture anomaly in 2000-21 and 19% in 2021."

The fraction of attributable risk framework reveals that the 2021 extreme [hydroclimatic intensity] is more likely to occur with anthropogenic forcing…than natural forcing alone.

"We estimate that climate change to date results in ~11% and ~15% increase in precipitation over the Feather River Basin in northern California for the first and second pulses."

"[I]t is hard to disentangle changes in the type of events that would occur in the area and the impact of climate change on each type of event."

"30-50% of the flooded properties would not have flooded without climate change."

"These findings illustrate that anthropogenic climate change is exacerbating autumn fire weather extremes that contribute to high-impact catastrophic fires in populated regions of the western US."

"Anthropogenically forced-warming and La Niña forced-precipitation deficits caused at least a sixfold risk increase for compound extreme low precipitation and high temperature in California–Nevada from October 2020 to September 2021."

"We show that nearly all of the observed increase in burned area over the past half-century is attributable to anthropogenic climate change."

"[P]erturbed CO2 experiments illuminate increases in CO2, causing a [lower] chance for [cold] extremes. "

"[P]erturbed CO2 experiments illuminate increases in CO2, causing a [higher] chance for [warm] extremes. "

"[W]e…show that human influence on the climate made this event at least 8 [2–50] times more likely."

"Human-induced warming from burning fossil fuels made the 5-day maximum temperature event about 1.4 degrees hotter and about 35 times more likely. For nighttime temperatures this is about 1.6C hotter and about 200 times more likely."

"[Greenhouse gas] emissions increase mean and extreme precipitation from rain gauge measurements across all seasons."

"Hurricane Beryl’s extreme winds in Jamaica were nearly twice as likely due to climate change  "