Changes

*[[Thermometer]]s that were once in rural areas are now surrounded by buildings which causes a 'heat island effect' which makes the [[reading]]s unreliable as there is another [[variable]] which has affected their [[temperature]] [[reading]]s.

*Old [[thermometer]]s were far less [[accurate]] than modern [[thermometer]]s. Some [[scientist]]s believe this is what caused an apparent halt in '''global warming''' over the last decade and in fact '''global warming''' didn't stop, we just got better [[thermometer]]s.

===References===

:[https://www.amazon.co.uk/gp/product/1471851346/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851346&linkCode=as2&tag=nrjc-21&linkId=3ac654f4b0da781c49c855a1af4c92ea ''Global warming; possible effects, pages 231-3, GCSE Chemistry, Hodder, AQA '']

:[https://www.amazon.co.uk/gp/product/1471851346/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851346&linkCode=as2&tag=nrjc-21&linkId=3ac654f4b0da781c49c855a1af4c92ea ''Global warming; scientific opinions, page 230, GCSE Chemistry, Hodder, AQA '']