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

Just Posted

NDP leader Jagmeet Singh to campaign in Port Alberni

Singh joins Courtenay-Alberni candidate for rally to kick off final weekend before election

Touring exhibit from Royal B.C. Museum highlights First Nations languages

Qualicum Beach Museum will be home to a variety of interactive stations

‘Dirty Money’ in Nanoose Bay: Dr. Peter German to speak at ElderCollege

‘This is an evolving study’: presenting up-to-date information on B.C. organized crime

Winter preparation underway for mid-Island highways

Drivers reminded to ready vehicles for changing conditions

Qualicum Beach council discusses helping out Orca Place residents

Town considers offer of temporary jobs in the future

ELECTION 2019: Have Justin Trudeau’s Liberals really cut middle-class taxes?

Conservative Andrew Scheer vows to cut bottom bracket, NDP’s Jagmeet Singh targets wealth tax

Vancouver Island’s West Coast going wild about cycling

Ongoing project will tie Tofino and Ucluelet together with a paved cycling trail

Drop, cover and hold on: Thousands of British Columbians to take part in earthquake drill

This year’s drill comes as scientists announce discovery of ‘stormquakes,’ an earthquake and hurricane

Woman, 24, faces life-altering injuries after being dragged 4 blocks by vehicle in Vancouver

A gofundme account says the woman will have to undergo multiple complex surgeries

Frustration and pride in Canada after a year of legal pot

It’s one year into Canada’s experiment in legal marijuana, and hundreds of legal pot shops have opened

West Kelowna business facing charges after six bears killed over littering

A West Kelowna business has been charged for leaving garbage around Lake Okanagan Resort

Fatal overdoses down by 33% in B.C., but carfentanil deaths continue to spike

Carfentanil, an illicit drug more powerful than fentanyl, causing more deaths than ever

One person hurt in crash at busy Nanaimo intersection

Minivan, sport utility vehicle collide at old Island Highway, Bowen Road and Norwell Drive

Most Read