So has it warmed at all?
Veteran meteorologists Joe D’Aleo and Anthony Watts analyzed temperature records from all around the world for a major SPPI paper, Surface Temperature Records – Policy-driven Deception? The startling conclusion that we cannot tell whether there was any significant “global warming” at all in the 20th century is based on numerous astonishing examples of manipulation and exaggeration of the true level and rate of “global warming”.
That is to say, leading meteorological institutions in the USA and around the world have so systematically tampered with instrumental temperature data that it cannot be safely said that there has been any significant net “global warming” in the 20th century.
SUMMARY FOR POLICYMAKERS
1. Instrumental temperature data for the pre-satellite era (1850-1980) have been so widely, systematically, and unidirectionally tampered with that it cannot be credibly asserted there has been any significant “global warming” in the 20th century.
2. All terrestrial surface-temperature databases exhibit very serious problems that render them useless for determining accurate long-term temperature trends.
3. All of the problems have skewed the data so as greatly to overstate observed warming both regionally and globally.
4. Global terrestrial temperature data are gravely compromised because more than three-quarters of the 6,000 stations that once existed are no longer reporting.
5. There has been a severe bias towards removing higher-altitude, higher-latitude, and rural stations, leading to a further serious overstatement of warming.
6. Contamination by urbanization, changes in land use, improper siting, and inadequately-calibrated instrument upgrades further overstates warming.
7. Numerous peer-reviewed papers in recent years have shown the overstatement of observed longer term warming is 30-50% from heat-island contamination alone.
8. Cherry-picking of observing sites combined with interpolation to vacant data grids may make heat-island bias greater than 50% of 20th-century warming.
9. In the oceans, data are missing and uncertainties are substantial. Comprehensive coverage has only been available since 2003, and shows no warming.
10. Satellite temperature monitoring has provided an alternative to terrestrial stations in compiling the global lower-troposphere temperature record. Their findings are increasingly diverging from the station-based constructions in a manner consistent with evidence of a warm bias in the surface temperature record.
11. NOAA and NASA, along with CRU, were the driving forces behind the systematic hyping of 20th-century “global warming”.
12. Changes have been made to alter the historical record to mask cyclical changes that could be readily explained by natural factors like multidecadal ocean and solar changes.
13. Global terrestrial data bases are seriously flawed and can no longer be trusted to assess climate trends or VALIDATE model forecasts.
14. An inclusive external assessment is essential of the surface temperature record of CRU, GISS and NCDC “chaired and paneled by mutually agreed to climate scientists who do not have a vested interest in the outcome of the evaluations.”
15. Reliance on the global data by both the UNIPCC and the US GCRP/CCSP also requires a full investigation and audit.
It is a point that all sceptics have conceded; the world has warmed in the last few decades. Coming out of an ice age and that CO2 is a greenhouse gas are facts. The debate has been on other points. Now a well researched report throws even that contention open to question.