Climate Change Impact On Biodiversity

By Paul Homewood

 

 

http://www.lwec.org.uk/resources/report-cards/biodiversity

 

I reported the other day about the new Channel 4  series concerning a “wildlife crisis caused by climate change in the UK”. Most of what they claimed was nothing more than unsubstantiated hype.

They say that the series is based around a new report from an outfit called “ Living With Environmental Change”, a partnership of 22 public sector organisations. So I thought I would delve into the report to see if it stands up to scrutiny.

The report, “Terrestrial Biodiversity Climate Change Impacts” lists a number of statements under the heading, “ What Has Happened” :-

 

 

1) Global and European temperatures have risen in recent decades and a large part of the warming can be attributed to human-induced climate change. In the UK, temperatures at many locations warmed, with the number of days warmer than 20°C having increased and the number of days colder than freezing having reduced in recent decades.

FACTCHECK

a) UK temperatures did increase up to 2006, but have been declining since.

b) CET 5-Year running average is back to 1990 levels.

c) There is no actual evidence of attribution to AGW.

 

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

 

2) Rainfall in the UK is highly variable from month to month and year to year, making it difficult to detect or attribute the cause of long-term trends. For the UK as a whole, recent decades have been getting wetter but this does mask a lot of regional and seasonal differences and may be part of natural variability. There are also signs that a greater proportion of rain is falling in more intense events.

FACTCHECK

a) Rainfall trends have increased since the mid 1970’s, at least in part because of the warm phase of the AMO. (See here).

 

 

b) There is no evidence that UK rainfall is becoming more variable – see here.

c) In recent years, winters have tended to become drier, and summers wetter. This is the total opposite of what the Met Office’s climate models have predicted – see here. This raises the question whether recent changes are related to global warming.

d) Evidence shows that extreme rainfall events are becoming neither more frequent, or intense – see here.

 

3) In the last decade or so, a number of extreme months or seasons have occurred in the weather record. In some cases, such as the European heat wave of summer 2003, there is evidence that human influence has changed the odds of such warm events happening.

FACTCHECK

a) Summer temperatures have been declining since 2006.

 

 

b) In terms of maximum temperature, 1976 remains by far the hottest summer on record.

c) Analysis of individual station records shows that extreme heat days have been much less common in the last decade, and that in the 1970’s and 1990’s were more common and hotter – see here.

 

4) Mean sea-levels are continuing to rise around the coast of the UK, driving an increase in extreme sea-levels.

FACTCHECK

a) After allowing for GIA ( land rising/falling), sea levels around the UK have not increased during the last ten years – see here.

b) Analysis of 20thC tide gauge records suggests an increase of about 6”/century, with no sign of an increasing trend – see here.

 

5) The magnitude and duration of winter river flooding has increased over the last 30 years, but a longer record is required to establish what is driving this change.

FACTCHECK

a) Winter precipitation trends have been falling in the last decade, and are now low by historical standards.

 

 

b) Analysis by Professor Stuart Lane of Durham University finds that “the period 1960-90 was an unusually dry one, especially compared to the 19th and early 20thC.” and “examining seasonal rainfall data and river flow patterns back to 1753, suggests many other “flood-rich periods” in the past which are comparable to now.” – see here.

 

6) Clear patterns of change in the occurrence of droughts have not been observed.

FACTCHECK

a) Certainly true. As we have already seen, rainfall has been increasing.

b) According to the Met Office, “The 2010/12 rainfall deficit was not as intense as 1975/76, which ranks as the most severe for the past 100 years in many respects” , and “Neither the development nor the severity of the 2010/12 drought was exceptional compared with historical events, and its climatological drivers have several similarities with past droughts.” -  See here.

 

7) 2012 was the second wettest year in the UK national record dating back to 1910, and just a few millimetres short of the record set in 2000. It featured a dry January to March which exacerbated a significant two-year drought, but this was followed by record rainfall in April and June. Summer 2012 was the second wettest for the UK overall and there were further periods of intense rainfall in the autumn and early winter. At present it is still unclear if humans have altered the odds of a year like 2012 occurring more frequently but this is an active area of research.

FACTCHECK

a) Based on the longer England & Wales Precipitation Index, both 1872 and 1768 were wetter years – see here.

b) Using the same index, 10-Year rainfall trends show no long term changes.

 

 

c) The Met Office admit they do not understand why the jet stream has moved southwards, thereby bringing higher rainfall, and can find no links to “climate change” – see here.

d) They also recognise that such jet stream movements have occurred in the past – see here.

 

Summary

1) They have identified certain changes in climate patterns during recent years, but have failed to provide evidence that :-

a) They are not natural variations.

b) They are in any way unprecedented.

2) While recognising that rainfall has been increasing, they have failed to point out the benefits this would bring in reducing droughts.

3) Much of the rise in temperatures over that last 30 years has been during Spring. In many ways this can be seen as beneficial to the environment and the biosphere. This does not appear to have been recognised in the report.

4) The report does not seem to have recognised changes in trends in recent years, which at this early stage may contradict some of their findings.

5) Claims about sea levels and extreme rain are inaccurate and misleading.

6) Claims about floods ignore the historical perspective, which shows they are in fact normal.

 

There have certainly provided little evidence to back up the claim that Britain’s wildlife is in crisis because of “climate change”.

 

 

References

The full report “Terrestrial Biodiversity Climate Change Impacts” is below.

http://www.lwec.org.uk/sites/default/files/Lwec_Report_Biodiversity_English_Web.pdf

 

All climate data is from the UK Met Office

http://www.metoffice.gov.uk/climate/uk/summaries