- Macquarie University ResearchOnline
... of different methods. Although a few climate reconstructions have been made using other types of palaeoenvironmental records, such as chironomid or coleopteran assemblages (e.g. Atkinson et al. 1987; Heiri et al. 2003), only pollen and plant macrofossil data are extensive enough to provide quantitat ...
... of different methods. Although a few climate reconstructions have been made using other types of palaeoenvironmental records, such as chironomid or coleopteran assemblages (e.g. Atkinson et al. 1987; Heiri et al. 2003), only pollen and plant macrofossil data are extensive enough to provide quantitat ...
Climate Change and Its Causes - The Science and Public Policy
... Figure 4: Climate sensitivity to CO2 doubling in function of the feedbacks (from Knutti and Hegerl [5]). Note the large uncertainty: a CO2 doubling may cause a global warming from 1 oC to 10 oC at equilibrium. The figure on the left explains why there exists such a large error. The GHG warming theo ...
... Figure 4: Climate sensitivity to CO2 doubling in function of the feedbacks (from Knutti and Hegerl [5]). Note the large uncertainty: a CO2 doubling may cause a global warming from 1 oC to 10 oC at equilibrium. The figure on the left explains why there exists such a large error. The GHG warming theo ...
Reconstruction of Summer Temperatures in Interior Alaska from
... and upland white spruce on low-elevation sites occupies both the warm and dry margin of the climatic range for the species (Thompson et al., 2000). Potential evapotranspiration during the growing season is often greater than annual precipitation (Patric and Black, 1968). In such environments, evapot ...
... and upland white spruce on low-elevation sites occupies both the warm and dry margin of the climatic range for the species (Thompson et al., 2000). Potential evapotranspiration during the growing season is often greater than annual precipitation (Patric and Black, 1968). In such environments, evapot ...
(2012), Global warming preceded by increasing carbon dioxide
... cores in the 1980s revealed that greenhouse gas concentrations also increased and decreased over the last glacial cycle2,3, suggesting they too may be part of the explanation. The ice-core record now extends back 800,000 yr and shows that local Antarctic temperature was strongly correlated with and ...
... cores in the 1980s revealed that greenhouse gas concentrations also increased and decreased over the last glacial cycle2,3, suggesting they too may be part of the explanation. The ice-core record now extends back 800,000 yr and shows that local Antarctic temperature was strongly correlated with and ...
Tree-Ring Amplification of the Early Nineteenth
... Annually resolved and absolutely dated tree-ring chronologies are the most important proxy archives to reconstruct climate variability over centuries to millennia. However, the suitability of tree-ring chronologies to reflect the ‘‘true’’ spectral properties of past changes in temperature and hydroc ...
... Annually resolved and absolutely dated tree-ring chronologies are the most important proxy archives to reconstruct climate variability over centuries to millennia. However, the suitability of tree-ring chronologies to reflect the ‘‘true’’ spectral properties of past changes in temperature and hydroc ...
Last millennium Northern Hemisphere summer temperatures from
... We seek a spatial reconstruction of past temperatures that utilizes a predictor network with a clear biophysical and statistical relationship with temperature. We therefore apply the expert knowledge of the original developers of the individual chronologies and reconstructions, relying on their expe ...
... We seek a spatial reconstruction of past temperatures that utilizes a predictor network with a clear biophysical and statistical relationship with temperature. We therefore apply the expert knowledge of the original developers of the individual chronologies and reconstructions, relying on their expe ...
Simple indices of global climate variability and change: Part I
... 2.1.2 Paleo-climate reconstructions In addition to the instrumental record described, the multi-proxy climate reconstructions of Mann et al. (2000a, b) have been used as a representation of surface temperature variations for the period 1700–1900. Previous studies have shown that these data can be us ...
... 2.1.2 Paleo-climate reconstructions In addition to the instrumental record described, the multi-proxy climate reconstructions of Mann et al. (2000a, b) have been used as a representation of surface temperature variations for the period 1700–1900. Previous studies have shown that these data can be us ...
Climate evolution in the last five centuries
... The global climate model consists of the spectral atmospheric model ECHAM4 (ROECKNER et al., 1996) and the ocean model HOPE-G (Wolff et al., 1997), both developed at the Max-Planck-Institute of Meteorology in Hamburg. In this simulation the model ECHAM4 has a horizontal resolution of T30 (approx. 3. ...
... The global climate model consists of the spectral atmospheric model ECHAM4 (ROECKNER et al., 1996) and the ocean model HOPE-G (Wolff et al., 1997), both developed at the Max-Planck-Institute of Meteorology in Hamburg. In this simulation the model ECHAM4 has a horizontal resolution of T30 (approx. 3. ...
Climate change between the mid and late Holocene in northern high
... by proxy data. The main forcing compared to the late preindustrial period is the insolation change due to the Earth’s slowly changing orbit around the sun (Hewitt and Mitchell, 1996; Kutzbach et al., 1996; Vettoretti et al., 1998; Joussaume et al., 1999). During the mid-Holocene, the seasonal cycle ...
... by proxy data. The main forcing compared to the late preindustrial period is the insolation change due to the Earth’s slowly changing orbit around the sun (Hewitt and Mitchell, 1996; Kutzbach et al., 1996; Vettoretti et al., 1998; Joussaume et al., 1999). During the mid-Holocene, the seasonal cycle ...
Using the IPCC`s Assessment Report data and climate change
... far more challenging review process should be involved. In my opinion, the IPCC reports cannot be described as peer reviewed, rather than a process of public comment” • David Holland stated “IPCC... Has failed to ensure that the experts… meet the required professional and ethical standards. The IPCC ...
... far more challenging review process should be involved. In my opinion, the IPCC reports cannot be described as peer reviewed, rather than a process of public comment” • David Holland stated “IPCC... Has failed to ensure that the experts… meet the required professional and ethical standards. The IPCC ...
Scientists - Environmental Defense Fund
... Counsel for amici curiae scientists hereby certifies, pursuant to D.C. Circuit Rule 29(d), that it is not practicable for these scientists to file a joint amicus brief with the other amici supporting petitioners and that it is thus necessary for the scientists to file a separate brief to state their ...
... Counsel for amici curiae scientists hereby certifies, pursuant to D.C. Circuit Rule 29(d), that it is not practicable for these scientists to file a joint amicus brief with the other amici supporting petitioners and that it is thus necessary for the scientists to file a separate brief to state their ...
Internal and forced climate variability during the last millennium: a
... number of records, Hughes and Diaz (1994) argued that, in some areas of the world, the temperatures were relatively high during the MWP, in particular in summer. However, in other regions such as the Southeastern United States or Southern Europe along the Mediterrranean Sea, the climate during that ...
... number of records, Hughes and Diaz (1994) argued that, in some areas of the world, the temperatures were relatively high during the MWP, in particular in summer. However, in other regions such as the Southeastern United States or Southern Europe along the Mediterrranean Sea, the climate during that ...
presenting - InterAcademy Council
... scientifically legitimate literature (e.g. peer reviewed literature, conference proceedings, reports of scientific institutes). Studies whose results and conclusions cannot be reconciled with a consensus view but which are of a good scientific and technical standard should be taken into account. The ...
... scientifically legitimate literature (e.g. peer reviewed literature, conference proceedings, reports of scientific institutes). Studies whose results and conclusions cannot be reconciled with a consensus view but which are of a good scientific and technical standard should be taken into account. The ...
Extracting and analyzing the warming trend in
... the NASA database (GN , N H N , SH N ; GISTEMP Team, 2015; Hansen et al., 2010). These databases di¤er basically in two aspects: 1) the way temperatures are extrapolated (or not) into regions without observing stations. This is particularly important since the HadCRUT4 excludes most of the Arctic, w ...
... the NASA database (GN , N H N , SH N ; GISTEMP Team, 2015; Hansen et al., 2010). These databases di¤er basically in two aspects: 1) the way temperatures are extrapolated (or not) into regions without observing stations. This is particularly important since the HadCRUT4 excludes most of the Arctic, w ...
A Summary of the Assessment Process of the Intergovernmental
... Prior to election of the Chair and Bureau, the Panel decides whether to undertake a comprehensive assessment, and sets a timetable for its completion. This determines the term of office of the Bureau. The decision to undertake the AR4 was taken in 2002. Similarly the Fifth Assessment round began wit ...
... Prior to election of the Chair and Bureau, the Panel decides whether to undertake a comprehensive assessment, and sets a timetable for its completion. This determines the term of office of the Bureau. The decision to undertake the AR4 was taken in 2002. Similarly the Fifth Assessment round began wit ...
INTERGOVERNMENTAL PANEL IPCC-XVIII/Doc. 2 ON CLIMATE
... consequences of climate change for least developed countries. In assuring the continued support of UNEP to the IPCC he referred explicitly to the recent decision 21/9 by the UNEP Governing Council. ...
... consequences of climate change for least developed countries. In assuring the continued support of UNEP to the IPCC he referred explicitly to the recent decision 21/9 by the UNEP Governing Council. ...
Climate variability over the last 2000 years
... years (e.g., Mann and Jones, 2003; Moberg et al., 2005). However, the association between change in temperature and change in atmospheric circulation under natural conditions has not been examined as vigorously. This association is perhaps most critical to investigate in the polar latitudes, where f ...
... years (e.g., Mann and Jones, 2003; Moberg et al., 2005). However, the association between change in temperature and change in atmospheric circulation under natural conditions has not been examined as vigorously. This association is perhaps most critical to investigate in the polar latitudes, where f ...
'A spaciotemporal analysis of U.S. station temperature trends over the last century
... climate dynamics, understanding the response of the climate system to different forcings is a challenging problem, involving analysis of the variations and trends in long time series of atmospheric measurements and proxy records. The global mean surface air temperature is one of the most important a ...
... climate dynamics, understanding the response of the climate system to different forcings is a challenging problem, involving analysis of the variations and trends in long time series of atmospheric measurements and proxy records. The global mean surface air temperature is one of the most important a ...
A spatiotemporal analysis of US station temperature trends over the
... climate dynamics, understanding the response of the climate system to different forcings is a challenging problem, involving analysis of the variations and trends in long time series of atmospheric measurements and proxy records. The global mean surface air temperature is one of the most important a ...
... climate dynamics, understanding the response of the climate system to different forcings is a challenging problem, involving analysis of the variations and trends in long time series of atmospheric measurements and proxy records. The global mean surface air temperature is one of the most important a ...
PowerPoint presentation (PPT file)
... characterized by relatively smaller uncertainties; Tier 3: Higher order methods involving detailed modeling and/or inventory measurement systems driven by data at a greater resolution that provide estimates with lower uncertainties than the previous two methods. ...
... characterized by relatively smaller uncertainties; Tier 3: Higher order methods involving detailed modeling and/or inventory measurement systems driven by data at a greater resolution that provide estimates with lower uncertainties than the previous two methods. ...
On forced temperature changes, internal variability
... The aforementioned EBM experiments have some important limitations. For example, the EBM does not account for potential changes in the flux of heat into the deep ocean, something that competes with both ECS and aerosol ERF in determining the response of surface temperatures to historical radiative fo ...
... The aforementioned EBM experiments have some important limitations. For example, the EBM does not account for potential changes in the flux of heat into the deep ocean, something that competes with both ECS and aerosol ERF in determining the response of surface temperatures to historical radiative fo ...
The Climate of the Last Millennium
... A.D. 1400, 397 records were used, but before A.D. 1400 this number drops to 14 (made up of 11 individual records, plus the first 3 principal components of tree ring width, representing a large set of trees in the western United States) (Mann et al. 1998, 1999). These paleoclimatic proxies were calib ...
... A.D. 1400, 397 records were used, but before A.D. 1400 this number drops to 14 (made up of 11 individual records, plus the first 3 principal components of tree ring width, representing a large set of trees in the western United States) (Mann et al. 1998, 1999). These paleoclimatic proxies were calib ...
Powerpoint version
... Summary: CO2 Data for the last 1800 years Data from early & modern measurements, Ice core, chemical and pine needles. Not a lot to scare, with this chart. Is the present CO2 increase not unusual, or are pine proxies not reliable? Of course, alarmists might say the latter - until they consider the p ...
... Summary: CO2 Data for the last 1800 years Data from early & modern measurements, Ice core, chemical and pine needles. Not a lot to scare, with this chart. Is the present CO2 increase not unusual, or are pine proxies not reliable? Of course, alarmists might say the latter - until they consider the p ...
An Engineer`s Critique of Global Warming `Science`
... Summary: CO2 Data for the last 1800 years Data from early & modern measurements, Ice core, chemical and pine needles. Not a lot to scare, with this chart. Is the present CO2 increase not unusual, or are pine proxies not reliable? Of course, alarmists might say the latter - until they consider the p ...
... Summary: CO2 Data for the last 1800 years Data from early & modern measurements, Ice core, chemical and pine needles. Not a lot to scare, with this chart. Is the present CO2 increase not unusual, or are pine proxies not reliable? Of course, alarmists might say the latter - until they consider the p ...
Hockey stick controversy
In the hockey stick controversy, the data and methods used in reconstructions of the temperature record of the past 1000 years have been disputed. Reconstructions have consistently shown that the rise in the instrumental temperature record of the past 150 years is not matched in earlier centuries, and the name ""hockey stick graph"" was coined for figures showing a long-term decline followed by an abrupt rise in temperatures. These graphs were publicised to explain the scientific findings of climatology, and in addition to scientific debate over the reconstructions, they have been the topic of political dispute. The issue is part of the global warming controversy and has been one focus of political responses to reports by the Intergovernmental Panel on Climate Change (IPCC). Arguments over the reconstructions have been taken up by fossil fuel industry funded lobbying groups attempting to cast doubt on climate science.The use of proxy indicators to get quantitative estimates of the temperature record of past centuries was developed from the 1990s onwards, and found indications that recent warming was exceptional. The Bradley & Jones 1993 reconstruction introduced the ""Composite Plus Scaling"" (CPS) method used by most later large-scale reconstructions, and its findings were disputed by Pat Michaels at the United States House Committee on Science.In 1998 Michael E. Mann, Raymond S. Bradley and Malcolm K. Hughes developed new statistical techniques to produce Mann, Bradley & Hughes 1998 (MBH98), the first eigenvector-based climate field reconstruction (CFR). This showed global patterns of annual surface temperature, and included a graph of average hemispheric temperatures back to 1400. In Mann, Bradley & Hughes 1999 (MBH99) the methodology was extended back to 1000. The term hockey stick was coined by the climatologist Jerry Mahlman, to describe the pattern this showed, envisaging a graph that is relatively flat to 1900 as forming an Ice hockey stick's ""shaft"", followed by a sharp increase corresponding to the ""blade"".A version of this graph was featured prominently in the 2001 IPCC Third Assessment Report (TAR), along with four other reconstructions supporting the same conclusion. The graph was publicised, and became a focus of dispute for those opposed to the strengthening scientific consensus that late 20th century warmth was exceptional.Those disputing the graph included Pat Michaels, the George C. Marshall Institute and Fred Singer. A paper by Willie Soon and Sallie Baliunas claiming greater medieval warmth was used by the Bush administration chief of staff Philip Cooney to justify altering the first Environmental Protection Agency Report on the Environment. The paper was quickly dismissed by scientists in the Soon and Baliunas controversy, but on July 28, Republican Jim Inhofe spoke in the Senate citing it to claim ""that man-made global warming is the greatest hoax ever perpetrated on the American people"".Later in 2003, a paper by Stephen McIntyre and Ross McKitrick disputing the data used in MBH98 paper was publicised by the George C. Marshall Institute and the Competitive Enterprise Institute. In 2004 Hans von Storch published criticism of the statistical techniques as tending to underplay variations in earlier parts of the graph, though this was disputed and he later accepted that the effect was very small. In 2005 McIntyre and McKitrick published criticisms of the principal components analysis methodology as used in MBH98 and MBH99. The analysis therein was subsequently disputed by published papers including Huybers 2005 and Wahl & Ammann 2007 which pointed to errors in the McIntyre and McKitrick methodology. In June 2005 Rep. Joe Barton launched what Sherwood Boehlert, chairman of the House Science Committee, called a ""misguided and illegitimate investigation"" into the data, methods and personal information of Mann, Bradley and Hughes. At Boehlert's request a panel of scientists convened by the National Research Council was set up, which reported in 2006 supporting Mann's findings with some qualifications, including agreeing that there were some statistical failings but these had little effect on the result. Barton and U.S. Rep. Ed Whitfield requested Edward Wegman to set up a team of statisticians to investigate, and they supported McIntyre and McKitrick's view that there were statistical failings, although they did not quantify whether there was any significant effect. They also produced an extensive network analysis which has been discredited by expert opinion and found to have issues of plagiarism. Arguments against the MBH studies were reintroduced as part of the Climatic Research Unit email controversy, but dismissed by eight independent investigations.More than two dozen reconstructions, using various statistical methods and combinations of proxy records, have supported the broad consensus shown in the original 1998 hockey-stick graph, with variations in how flat the pre-20th century ""shaft"" appears. The 2007 IPCC Fourth Assessment Report cited 14 reconstructions, 10 of which covered 1,000 years or longer, to support its strengthened conclusion that it was likely that Northern Hemisphere temperatures during the 20th century were the highest in at least the past 1,300 years. Over a dozen subsequent reconstructions, including Mann et al. 2008 and PAGES 2k Consortium 2013, have supported these general conclusions.