Ours is the usual claim based on treating the evidence in a usual manner ... temperatures have gone up 1ºC in the past 140 years ... where has climate changed? ... we "expect" temperatures to rise another 1ºC in the next 140 years ... where will climate change? ... if both answers above are "no where" ... then climate isn't changing ... what more proof do you need? ...
Let's see your proof that man has a MEASURABLE effect on the weather ... and show your math ... (hint: think "clearcutting") ...
From
https://crsreports.congress.gov/product/pdf/R/R47082#:~:text=The AR6 WGI presents current,greater intensity since the 1950s,
Human Influence on Planetary Warming
The question of whether and how human activity, among other potential drivers, has contributed to climate change has been discussed and debated for many years. Scientists have considered many potential natural and human-induced drivers of climate change and have examined these influences for their effect on the current climate using evidence from both historical and geological records. Each version of the WGI report has included a precisely worded assessment of the human role in climate change, which has been monitored by many governments, news media, and civil society organizations around the world. Among the central findings of the AR6 WGI was the following: “It is unequivocal that human influence has warmed the atmosphere, ocean, and land.”
The statement is supported by a mechanism of human influence—the increases in well-mixed10 greenhouse gases (GHGs),11 including CO2, methane (CH4), nitrous oxide (N2O), and halogenated gases (e.g., chlorofluorocarbons [CFCs], hydrochlorofluorocarbons [HCFCs], and hydrofluorocarbons [HFCs]) in the atmosphere: “Observed increases in well-mixed greenhouse gas (GHG) concentrations since around 1750 are unequivocally caused by human activities.” 12 The heat-trapping character of GHGs in the atmosphere is one of their known physical properties.13
The AR6 WGI statement on human influence on warming differs from the earlier assessment of human influence included in the 2014 IPCC Fifth Assessment Report (AR5),14 which states that anthropogenic GHGs (i.e., those emitted through human activity) “are extremely likely15 to have been the dominant cause of the observed warming since the mid-20th century.” 16
Currently Observed Climate Changes
AR6 WGI states that from about 1750 to the present, 24 “Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.” 25 AR6 WGI presents numerous changes observable in data obtained from monitoring of the climate and climate-sensitive aspects of the earth system. The report identifies where climate-related changes are detectable, and with some detectable changes, the report assesses the likelihoods that a particular change is attributable to human influence. AR6 WGI states varying levels of confidence in being able to attribute observed changes to human influence. Further, there are varying levels of certainty about whether particular changes are influenced by human activity, and these are also reported explicitly.26 The changes that are observed are not uniform with respect to their extent, the direction of the change, or the regional character of the change. As illustrated in the following quotation, the AR6 WGI concludes that changes in extremes of hot and cold are virtually certain to have occurred: It is virtually certain that hot extremes (including heatwaves) have become more frequent and more intense across most land regions since the 1950s, while cold extremes (including cold waves) have become less frequent and less severe, with high confidence that humaninduced climate change is the main driver of these changes. Some recent hot extremes observed over the past decade would have been extremely unlikely to occur without human influence on the climate system.27 One manifestation of large-scale regional differences in the results of climate change is the observed quantity and extent of polar sea ice. Seasonal Arctic sea ice has decreased since 1979, a trend that is very likely to have been human induced, while seasonal Antarctic sea ice has remained unchanged in the same period.28 Retreat of glaciers is a consistent global phenomenon across many regions and assessed as very likely to have been influenced by human activity. The warming of the upper ocean since the 1970s is a globally consistent trend that is virtually certain and for which AR6 WGI states human influence to be extremely likely:29 “ocean warming is largest near the surface, and the upper 75 m warmed by 0.11 [0.09 to 0.13] °C per decade over the period 1971 to 2010.”30
AR6 WGI states that there have likely been changes in the occurrence of major tropical cyclones, but the findings regarding trends and attribution are less certain: It is likely that the global proportion of major (Category 3–5) tropical cyclone occurrence has increased over the last four decades ... these changes cannot be explained by internal variability alone (medium confidence). There is low confidence in long-term (multidecadal to centennial) trends in the frequency of all-category tropical cyclones.31
Unprecedented Changes in the Climate System
AR6 WGI states that some of the changes in the climate, or their observable effects, are unprecedented on a scale of centuries to millennia. This assessment is based on groups of studies estimating past CO2, CH4, and N2O atmospheric concentrations, using a variety of analytic techniques, to cover periods going back 800,000 years for CH4 and N2O, and longer periods for CO2. In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years (high confidence), and concentrations of CH4 and N2O were higher than at any time in at least 800,000 years (very high confidence). Since 1750, increases in CO2 (47%) and CH4 (156%) concentrations far exceed—and increases in N2O (23%) are similar to—the natural multi-millennial changes between glacial and interglacial periods over at least the past 800,000 years (very high confidence).32 In AR6 WGI there is medium confidence that global surface temperatures are now higher than they have been for thousands of years (see Figure 2, panel (a)). Temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6500 years ago [0.2°C to 1°C relative to 1850–1900] (medium confidence). Prior to that, the next most recent warm period was about 125,000 years ago, when the multi-century temperature [0.5°C to 1.5°C relative to 1850–1900] overlaps the observations of the most recent decade (medium confidence).33
REFERENCES
9 IPCC, “Summary for Policymakers,” in Climate Change 2021: The Physical Science Basis—Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, 2021, p. 4 (hereinafter IPCC SPM WGI 2021).
10 The glossary in IPCC WGI 2021 defines well-mixed greenhouse gas as follows: Well-mixed greenhouse gas.... A greenhouse gas that has an atmospheric lifetime long enough (> several years) to be homogeneously mixed in the troposphere, and as such the global average mixing ratio can be determined from a network of surface observations. For many well-mixed greenhouse gases, measurements made in remote regions differ from the global mean by < 15%.
11 The glossary in IPCC, Climate Change 2014: Mitigation of Climate Change—Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, 2014, provides the following definition of greenhouse gases: Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of terrestrial radiation emitted by the earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.
12 IPCC SPM WGI 2021, p. 4.
13 CRS Report R45086, Evolving Assessments of Human and Natural Contributions to Climate Change, by Jane A. Leggett.
14 IPCC, Climate Change 2014: Synthesis Report—Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, 2014 (hereinafter IPCC AR5 WGI,II,III 2014)
15 IPCC notes the following in Climate Change 2014: Mitigation of Climate Change—Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, 2014: In the Synthesis Report, the certainty in key assessment findings is communicated as in the Working Group Reports and Special Reports. It is based on the author teams’ evaluations of underlying scientific understanding and is expressed as a qualitative level of confidence (from very low to very high) and, when possible, probabilistically with a quantified likelihood (from exceptionally unlikely to virtually certain). Where appropriate, findings are also formulated as statements of fact without using uncertainty qualifiers.
16 IPCC AR5 WGI,II,III 2014, p. 17.
17 IPCC SPM WGI 2021, p. 5.
18 IPCC SPM WGI 2021, p. 4: Each finding is grounded in an evaluation of underlying evidence and agreement. A level of confidence is expressed using five qualifiers: very low, low, medium, high and very high, and typeset in italics, for example, medium confidence. The following terms have been used to indicate the assessed likelihood of a outcome or result: virtually certain 99–100% probability; very likely 90–100%; likely 66–100%; about as likely as not 33–66%; unlikely 0–33%; very unlikely 0–10%; and exceptionally unlikely 0–1%. Additional terms (extremely likely 95–100%; more likely than not >50–100%; and extremely unlikely 0–5%) are also used when appropriate. Assessed likelihood is typeset in italics, for example, very likely. This is consistent with AR5. In this Report, unless stated otherwise, square brackets [x to y] are used to provide the assessed very likely range, or 90% interval.
19 For explanation of climate, climate variability, and climate change, see CRS In Focus IF11446, Weather and Climate Change: What’s the Difference?, by Jane A. Leggett.
20 The U.S. Geological Survey defines anthropogenic as “referring to environmental change caused or influenced by people, either directly or indirectly.” See U.S. Geological Survey, Earthword: Anthropogenic,
USGS.gov | Science for a changing world news/science-snippet/earthword-anthropogenic.
21 IPCC SPM WGI 2021, p. 5.
22 The Montreal Protocol is an international treaty for the control of substances that deplete the stratospheric ozone layer. See U.S. Department of State, The Montreal Protocol on Substances That Deplete the Ozone Layer,
https://www.state.gov/key-topics-of...ol-onsubstances-that-deplete-the-ozone-layer/.
24 IPCC SPM WGI 2021, pp. 4-6.
25 IPCC SPM WGI 2021, p. 4.
26 Where statements of levels of certainty appear in this CRS report, they are sourced from AR6 WGI unless stated otherwise.
27 IPCC SPM WGI 2021, p. 8.
28 IPCC SPM WGI 2021, p. 5.
29 IPCC SPM WGI 2021, p. 5.
30 IPCC WGI 2021, p. 1-168.
31 IPCC SPM WGI 2021, p. 9.
32 IPCC SPM WGI 2021, p. 8.
33 IPCC SPM WGI 2021, p. 8.
