Seeing the environmental forest

That is the conclusion of a new study published in Science yesterday.  Tom Karl and his co-authors used a newly available database of weather station data that combined the Global Historical Climatology Network (GHCN) used by NOAA and NASA with over 40 other historical data sources, effectively doubling the size of the available land temperature data set.  They applied the same corrections for changes in location, urban heat island effect, etc as with the GHCN-only data set and used the same algorithms to calculate the global average over land.  To get a global average, they used the Extended Reconstructed Sea Surface Temperature dataset version 4 (ERSST4), which better integrates ship-based temperature data and buoy-based temperature data, and merged it with their new land data.  Karl et al. then created a third global temperature average that also fills in the gaps between weather stations in the polar regions. Their new data set shows much higher trends than th...

Regular readers of this blog will know that I am skeptical of claims that global warming in atmospheric temperatures have paused since 1998, having written several posts questioning the existence of such a pause.  In this edition, I'll run down the main evidence that, in my opinion, show that the pause is a figment of the denialsphere's imagination.

Given that 2014 is nearly over (~3 weeks to go), we're going to be hearing even more about the possibility that 2014 will be the warmest year in the instrumental record.  I myself made the pile higher and deeper with my last post .  That raised a question in my mind: Where should global temperature be in 2014 according to the warming trend since 1979 (the first full year of the satellite record)?

It seems the canard about how IPCC models are inaccurate just won't go away.  I've covered it before on this blog .  The newest incarnation of that canard revolves around a new paper by Risbey et al. ( 2014 ).  It seems that many just don't understand what Risbey et al. did and they definitely don't understand the results of that paper.

Much has been made of the pause in global surface temperatures since 1998.  Among the factors advanced to explain that pause include a change in ENSO, a decline in solar output, and an increase in aerosols (i.e. Foster and Rahmstorf 2011 ).  One of the previously neglected factors is artificial cooling in global surface temperature data sets.  Neither the HadCRUT4 nor the NOAA temperature data cover the polar regions.  As the polar regions are the fastest warming areas on Earth (UAH Arctic trend since November 1978: +0.44ºC per decade, Global trend: +0.14ºC per decade), excluding those regions leads to an artificial cooling bias in the data. Anomaly map of HadCRUT4, showing the gaps in data coverage (in white) Both NOAA and GISS are artificially cooled by an outdated ocean temperature data set (HadSST2) that doesn't account for the change from ship-based temperature measurements to buoy-based temperature measurements that occurred within the last 10 years ( ...