Taking the planet’s temperature: How are global temperatures calculated?

Grantham intern Peter Davies (Department of Physics) delves into global temperature records. Statements such as “2014 earth’s warmest year on record” or “No global warming for 18 years 1 month” are conclusions from different atmospheric temperature data sets.  Before assessing which is true it is important to understand how temperatures are measured, how data sets are created and used to calculate global temperatures, and the … Continue reading Taking the planet’s temperature: How are global temperatures calculated?

2014 – the warmest year on record

A summary of global temperature for 2014 from NASA and NOAA has just been published, showing that the average global temperature for 2014 was 0.69°C above the average for the 20th century. The small margin of uncertainty in calculating average global temperature means that the exact ranking of 2014 cannot be distinguished from the previous record years of 2005 and 2010, but it is nominally … Continue reading 2014 – the warmest year on record

2°C or not 2°C – should we ditch the below 2°C target for global warming?

By Professor Joanna Haigh, Co-Director, Grantham Institute A commentary published in Nature this week has opened up a discussion about the value of using the goal of keeping global warming to below 2°C. David Victor and Charles Kennel are concerned that the below 2°C target for global warming is not useful, partly because they consider it is no longer achievable and partly because global mean surface … Continue reading 2°C or not 2°C – should we ditch the below 2°C target for global warming?

Ocean heat uptake – checking the facts

By Dr Flora Whitmarsh, Grantham Institute The recent slowdown in global temperature rise has led to suggestions that global warming has stopped. In fact, the Earth system is still gaining heat, and the slowdown was likely caused by a series of small volcanic eruptions, a downward trend in the solar cycle, and increased heat uptake of the ocean. Writing in the Telegraph, Christopher Booker claims … Continue reading Ocean heat uptake – checking the facts