In a subsequent report, the IPCC defines it as:

The Intergovernmental Panel on Climate Change ( IPCC ) has concluded that " of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.

In the IPCC Fourth Assessment Report, the following scale is used to quantify uncertainty: " virtually certain " > 99 %; " extremely likely " > 95 %; " very likely " > 90 %; " likely " > 66 %; " more likely than not " > 50 %; " about as likely as not " 33 to 66 %; " unlikely " < 33 %; " very unlikely " < 10 %; " extremely unlikely " < 5 %; " exceptionally unlikely " < 1 %.

As assessed by the Intergovernmental Panel on Climate Change ( IPCC ), " of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations ".

The 2007 IPCC Fourth Assessment Report cited 14 reconstructions, 10 of which covered 1, 000 years or longer, to support its conclusion that " Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1, 300 years ".

Following the IPCC Fourth Assessment Report, the declaration states, " It is unequivocal that the climate is changing, and it is very likely that this is predominantly caused by the increasing human interference with the atmosphere.

The IPCC's moderate warming scenarios ( B1 to A1T, 2 ° C by 2100, IPCC, 2007, Table SPM. 3, p. 13 ) forecast that corals on the Great Barrier Reef are very likely to regularly experience summer temperatures high enough to induce bleaching.

In the early nighties the hCa initiative very much resembled other large international networks, like the END-Convention and IPCC ( International Peace Communication and Coordination Center ) and many of the activists and organizations of END and IPCC joined the hCa.

The IPCC concluded the warmest period prior to the 20th century very likely occurred between 950 and 1100 ... The evidence currently available indicates that NH mean temperatures during medieval times ( 950 – 1100 ) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century ( Osborn and Briffa, 2006 ).

: " very few " scientists disputed the latest IPCC report.

This value is estimated, by the IPCC Fourth Assessment Report ( AR4 ) as likely to be in the range 2 to 4. 5 ° C with a best estimate of about 3 ° C, and is very unlikely to be less than 1. 5 ° C.

Details like sea level rise will continue to be debated by researchers, but if the debate over whether or not humanity is contributing to global warming wasn't over before, it is now ... as the new IPCC Summary makes clear, climate change Pollyannaism is no longer looking very tenable.

" Very likely " here is defined by the IPCC as having a likelihood of greater than 90 %, based on expert judgement.

Carbon dioxide produced from fossil fuels is one of the greenhouse gases indicated by the Intergovernmental Panel on Climate Change ( IPCC ) to be a " most likely " cause of global warming.

The two Mann, Bradley & Hughes studies, together with, and others formed a major part of the IPCC Third Assessment Report's conclusion that " the rate and magnitude of global or hemispheric surface 20th century warming is likely to have been the largest of the millennium, with the 1990s and 1998 likely to have been the warmest decade and year ".

In a 2007 ruling in a trial relating to automobile emission regulation in Vermont, U. S. District Court Chief Judge William K. Sessions wrote, " Plaintiffs ’ own expert, Dr. Christy, agrees with the IPCC ’ s assessment that in the light of new evidence and taking into account remaining uncertainties, most of the observed warming over the last fifty years is likely to have been due to the increase in GHG concentrations.

US NRC ( 2001 ) generally agrees with findings of the WG I report, for example, US NRC ( 2001 ) state that " IPCC ’ s conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue.

" This estimate of climate sensitivity has been essentially unchanged for over three decades, e. g., the IPCC Fourth Assessment Report ( 2007 ) says that " equilibrium climate sensitivity is likely to be in the range 2 ° C to 4. 5 ° C, with a best estimate value of about 3 ° C.

The SRES scenarios were not assigned probabilities by the IPCC, but some authors have argued that particular SRES scenarios are more likely to occur than others.

The IPCC has received the Nobel Peace Prize in 2007 " for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change.

:... the Nobel Peace Prize for 2007 is to be shared, in two equal parts, between the Intergovernmental Panel on Climate Change ( IPCC ) and Albert Arnold ( Al ) Gore Jr. for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change.

The 2007 prize went to Al Gore and the IPCC, " for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change ".

Benjamin D. Santer, a climate change researcher, wrote: The Global Climate Coalition-a less than disinterested party-has made serious allegations regarding the scientific integrity of the Lead Authors of Chapter 8, and of the IPCC process itself.

The IPCC stated that " it is well-known that compared to non-urban areas urban heat islands raise night-time temperatures more than daytime temperatures.

In 2007, more than 20 PNNL scientists were recognized for their contributions to the Intergovernmental Panel on Climate Change ( IPCC ) that received the 2007 Nobel Peace Prize in equal parts with former Vice President Al Gore.

At 106 g CO < sub > 2 </ sub >/ MJ, the carbon dioxide emissions of peat are higher than those of coal ( at 94. 6 g CO < sub > 2 </ sub >/ MJ ) and natural gas ( at 56. 1 ) ( IPCC ).

The IPCC Fourth Assessment Report found that the instrumental temperature record for the past century included urban heat island effects but that these were primarily local, having a negligible influence on global temperature trends ( less than 0. 006 ° C per decade over land and zero over the oceans ).

They point to such numbers as the Intergovernmental Panel on Climate Change ( IPCC ) assumption that a developed nation can pay fifteen times more than a developing nation to avert a death due to climate change, as evidence of systematic neglect of the value of statistical life in the poorer South, as opposed to the more developed North.

And, though I would not have said so a decade ago, I now believe, as does the IPCC, that there is no more than a one in three chance that the observed global warming over the past century is entirely natural in origin.

Emissions data are reported to the IPCC as contributions of producing industries located in a particular country rather than as embodiments in products consumed by a particular population, irrespective of productive origin.

James E. Hansen has argued that multiple positive feedbacks could lead to nonlinear ice sheet disintegration much faster than claimed by the IPCC.

The most recent research using data from 1996 to 2005 shows that the ice sheet is thinning even faster than supposed by IPCC.

The Intergovernmental Panel on Climate Change ( IPCC ) stated in its Fourth Assessment Report ( AR4 ) that the temperature rise over the 100 year period from 1906 – 2005 was 0. 74 ° C to 0. 92 ° C with a confidence interval of 90 %.

He said the leaked e-mails showed that the " surface temperature data that IPCC relies on is based on distorted raw data and algorithms that they will not share with the science community.

This EPA estimate is based on methodologies agreed to by the Conference of Parties of the UNFCCC, with 100-year global warming potentials from the IPCC Second Assessment Report used in estimating GHG emissions as carbon dioxide equivalents.

The central message of both the IPCC reports and the Sir Nicholas Stern reports to us, world leaders, is crystal clear: unless urgent actions are done to curb greenhoses gasses emissions by shifting to a new global energy mix based on renewable energy sources, and unless timely adaptation is done, the adverse impact of climate change on all communities, will be catastrophic.

* Global Warming-Frequently Asked Questions NCDC report prepared by Karl and David Easterling based on IPCC TAR and other sources.

This contrasts sharply with the principles upheld by the IPCC ( Intergovernmental Panel on Climate Change ), which allow only to assess the current knowledge based on the best available, peer reviewed scientific literature and which do not allow for any non-scientific value judgements, let alone policy recommendations.

IPCC First Assessment Report | IPCC FAR 1990 Figure 7. 1. c ( red ) based on Lamb 1965 showing central England temperatures ; central England temperatures to 2007 shown from Jones et al.

Other projections are based on scenarios that the IPCC has developed.

* In January 2010, the Sunday Times published an article alleging that a figure in the IPCC Fourth Assessment Report was based on an " unsubstantiated claim ".

The IPCC's Commissioners and staff are based in IPCC regional offices in Cardiff, London, Sale and Wakefield.