Clarifying global warming ‘hiatus’

Having worked in government agencies on climate change, and published on the issue, I would like to try to clarify some of the points raised in David Patterson’s letter of June 27 on the global warming ‘hiatus’.

The hiatus is an interval of slower rise in global temperatures, and many respected climate scientists agree that a hiatus has recently occurred. Virtually all climate scientists agree that natural variability (often as cycles) contributes to global temperatures, and some scientists think such variability may be the cause of the hiatus.

But Mr. Patterson’s letter may provoke climate change skeptics to say that the rise is due only to natural variability and not to man, or that any hiatus is proof of that. Mr. Patterson is right to support the scientific consensus that the measured rise in global temperatures since around 1850 is largely due to man; natural variability is a secondary contributor to this temperature record.

Recent papers suggest there may have been three hiatus intervals in the post-1850 record, the intervals starting around 1880, 1940 and 1998.

The cause may be a natural up-and-down cycle with its downturns starting at those times, but the temperature rise from man’s emissions of greenhouse gases almost overwhelms any such natural variability.

This is why the presence of a hiatus is often unclear, particularly over the last decade or two when the temperature rise from greenhouse emissions has been so marked.

Norman Treloar

Qualicum Beach

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Qualicum Beach volunteer Mark Watson honoured for 30 years of service at fire hall

‘He has such a good spirit in everything that he does’

MLAs say Parksville will better prepared for flooding emergencies

RDN receives $150K in funding for Englishman River Flood Hazard Mapping project

B.C. sees 25 new COVID-19 cases, community exposure tracked

One death, outbreaks remain in two long-term care facilities

B.C. man prepares to be first to receive double-hand transplant in Canada

After the surgery, transplant patients face a long recovery

Grocers appear before MPs to explain decision to cut pandemic pay

Executives from three of Canada’s largest grocery chains have defended their decision to end temporary wage increases

RCMP ‘disappointed’ by talk that race a factor in quiet Rideau Hall arrest

Corey Hurren, who is from Manitoba, is facing 22 charges

NHL’s Canadian hubs offer little economic benefit, but morale boost is valuable: experts

Games are slated to start Aug. 1 with six Canadian teams qualifying for the 24-team resumption of play

‘Made in the Cowichan Valley’ coming to a wine bottle near you

Cowichan Valley has the honour of being the first sub-GI outside of the Okanagan

Comox Valley RCMP looking for missing woman

Ami Guthrie was last seen in Courtenay in early July

VIDEO: Vancouver Island cat missing 18 months reunited with family

Blue the cat found at Victoria museum 17 kilometres from home

VIDEO: Alberta man rescues baby eagle believed to be drowning in East Kootenay lake

Brett Bacon was boating on a lake in Windermere when he spotted the baby eagle struggling in the water

Most Read