page_title: Global warming controversy
section_title: Instrumental record of surface temperature
hierarchical_section_title: Global warming controversy / Scientific consensus / Analysis of temperature records / Instrumental record of surface temperature
context_page_description: The global warming controversy concerns the public debate over whether global warming is occurring, how much has occurred in modern times, what has caused it, what its effects will be, whether any action can or should be taken to curb it, and if so what that action should be. In the scientific literature, there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases. No scientific body of national or international standing disagrees with this view, though a few organizations with members in extractive industries hold non-committal positions, and some have attempted to convince the public that climate change isn't happening, or if the climate is changing it isn't because of human influence, attempting to sow doubt in the scientific consensus.
  The controversy is, by now, political rather than scientific: there is a scientific consensus that global warming is happening and is caused by human activity.
context_section_description: There have been attempts to raise public controversy over the accuracy of the instrumental temperature record on the basis of the urban heat island effect, the quality of the surface station network, and assertions that there have been unwarranted adjustments to the temperature record.
  Weather stations that are used to compute global temperature records are not evenly distributed over the planet, and their distribution has changed over time. There were a small number of weather stations in the 1850s, and the number didn't reach the current 3000+ until the 1951 to 1990 period
  The 2001 IPCC Third Assessment Report (TAR) acknowledged that the urban heat island is an important local effect, but cited analyses of historical data indicating that the effect of the urban heat island on the global temperature trend is no more than 0.05 °C (0.09 °F) degrees through 1990.
  Peterson (2003) found no difference between the warming observed in urban and rural areas.
  Parker (2006) found that there was no difference in warming between calm and windy nights. Since the urban heat island effect is strongest for calm nights and is weak or absent on windy nights, this was taken as evidence that global temperature trends are not significantly contaminated by urban effects. Pielke and Matsui published a paper disagreeing with Parker's conclusions.
  In 2005, Roger A. Pielke and Stephen McIntyre criticized the US instrumental temperature record and adjustments to it, and Pielke and others criticized the poor quality siting of a number of weather stations in the United States. In 2007, Anthony Watts began a volunteer effort to photographically document the siting quality of these stations. The Journal of Geophysical Research – Atmospheres subsequently published a study by Menne et al. which examined the record of stations picked out by Watts' Surfacestations.org and found that, if anything, the poorly sited stations showed a slight cool bias rather than the warm bias which Watts had anticipated.
  The Berkeley Earth Surface Temperature group carried out an independent assessment of land temperature records, which examined issues raised by skeptics, such as the urban heat island effect, poor station quality, and the risk of data selection bias. The preliminary results, made public in October 2011, found that these factors had not biased the results obtained by NOAA, the Hadley Centre together with the Climatic Research Unit (HadCRUT) and NASA's GISS in earlier studies. The group also confirmed that over the past 50 years the land surface warmed by 0.911 °C, and their results closely matched those obtained from these earlier studies. The four papers they had produced had been submitted for peer review.
caption: temperature variations during the present geological age
exif: {}