New UN report on climate change says some effects ‘irreversible’ over hundreds, thousands of years

climate change

Scientists are seeing changes in the earth’s climate in “every region and across the whole climate system,” according to a new report released Monday from the United Nations’ Intergovernmental Panel on Climate Change (IPCC), and in many cases the changes are irreversible in the short term.

According to the report, what is being observed by scientists is “unprecedented” and has set in motion changes that will be “irreversible over hundreds to thousands of years,” including rising sea levels.

The IPCC says “strong and sustained” reductions in greenhouse gases including carbon dioxide would limit climate change and air quality would come quickly, noting “it could take 20-30 years to see global temperatures stabilize.”

“This report is a reality check,” says Valérie Masson-Delmotte, co-chair of an IPCC working group. “We now have a much clearer picture of the past, present and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare.”

The report says there must be “immediate, rapid and large-scale reductions” in greenhouse gas emissions or else limiting global warming to 1.5 C “or even” 2 C will be “beyond reach.”


Forest fires, scorching temperatures, sea creatures and salmon

The IPCC report comes out as parts of the B.C. interior, Manitoba and Ontario battle large-scale forest fires under extreme, unprecedented temperatures. One town in B.C. burned to the ground, and according to researchers at the University of British Columbia, one billion seashore creatures died because of the oppressive heat.

Scott Hinch, director of the Pacific salmon ecology and conservation laboratory at UBC, told The Canadian Press in July that juvenile salmon such as sockeye, Coho and chinook in fresh water would have been most affected by recent heat waves.

“They’re going to be living in fresh water for one to two years and it’s that life history stage, that this particular heat wave and just climate change in fresh water in particular, is going to have some of its greatest effects,” he says.

Salmon in British Columbia are already at risk due to a combination of factors, including changing climate, mining, logging, habitat loss and the Fraser River landslide.

The Fraser is one of the largest spawning rivers in the world and the landslide, discovered in 2019, decimated early runs of Stuart sockeye and chinook salmon.

The Committee on the Status of Endangered Wildlife in Canada has classified Sakinaw sockeye, Okanagan chinook and certain species of Fraser sockeye as endangered. It classified Interior Fraser Coho and some of Fraser sockeye as threatened and is assessing the status of chinook.

Hinch says the ideal water temperature for salmon is between 12 C and 18 C and they can only stand the heat for so long.

The heat wave in June where the all-time Canadian temperature record was set saw water in streams hit the mid-20s, “and those are really stressful for juvenile salmon, and lethal,” he said.

“We start seeing really bad things happening when temperatures are at 24 degrees or above.”

There’s a lot less oxygen in warm water and deep water is cooler than the surface, where the juvenile salmon need to feed.

The Ministry of Forests says about 270 wildfires are currently burning, most in the southern Interior, with just eight sparked over the last two days.

One of the most concerning remains the White Rock Lake fire between Kamloops and Okanagan Lake, which has scorched nearly 560-square kilometres, destroyed properties east of Kamloops and forced thousands from their homes.

It is burning in one of two B.C. regions still ranked at high to extreme risk of wildfires but a damp weekend cut the chance of embers flying across Okanagan Lake, allowing Vernon to lift its evacuation alert – although orders or alerts from three regional districts, two communities and two First Nations are still in place.

Scientists involved in a federal government report released in January predict extreme weather events will get more severe and could present the most challenging, and expensive, consequence of climate change in the three Prairie provinces of Manitoba, Saskatchewan and Alberta.

That means more intense rain generating more powerful floods. It means hotter summers, drier tinder and more destructive wildfires in a region that, within the last seven years, witnessed two of the costliest weather-related disasters in Canadian history.

“There’s good scientific evidence, now, that the severity of these events is worse because they’re occurring in a warmer climate,” said Dave Sauchyn, director of the Prairie Adaptation Research Collaborative at University of Regina, in an interview.

“We call it the amplification – amplifying or enhancing the severity of these events. This effect will only increase as the climate gets warmer.”

In other parts of the world, Greece continues to be ravaged by fires that are swallowing towns and villages and in the United States, a third of the country is experiencing some level of drought.

Floods in Europe have also killed hundreds of people.

In the 2019-20 Australian bushfire season, the world watched as 10 million hectares were scorched and a billion animals died.

“These stark warnings from the world’s top climate scientists should inform the election platform of every party in Canada’s upcoming election,” says Keith Stewart, senior energy strategist for Greenpeace Canada in a statement about the report.

“We know that the killer heat waves and wildfires, devastating droughts, flash floods and rising seas will only become more frequent and more extreme until we stop burning fossil fuels and protect the ecosystems that store carbon. As one of the world’s largest producers and exporters of fossil fuels, Canada is currently a big part of the problem but we can and should be an even bigger part of the solution.”

Influence on types of weather

climate change


According to the IPCC report, warming over land is larger than the global average, and it is more than twice as high in the Arctic.

“Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming,” says IPCC Working Group Co-Chair Panmao Zhai.

The report says there will be an increase in heat waves, longer warm seasons and shorter cold seasons.

“At 2°C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health,” the report says.

The IPCC says climate change is more than about temperature. There will be changes to wetness, dryness, winds, snow and ice, coastal areas and oceans.

Specifically, some of the changes the IPCC is warning about are; more intense rainfalls and associated flooding, droughts in many regions,.

“Coastal areas will see continued sea level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion,” the report says. “Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century.”

Also, further warming will “amplify permafrost thawing, and the loss of seasonal snow cover, melting of glaciers and ice sheets, and loss of summer Arctic sea ice.”

The report states that changes to the ocean will cause more frequent heatwaves, ocean acidification and reduced oxygen levels that will “affect both ocean ecosystems and the people that rely on them, and they will continue throughout at least the rest of this century.”

People living in cities will experience higher temperatures and flooding from “heavy precipitation.”


The IPCC has developed a regional interactive web page people can explore information about their territory.

“It has been clear for decades that the Earth’s climate is changing, and the role of human influence on the climate system is undisputed,” says Masson-Delmotte. “Yet the new report also reflects major advances in the science of attribution – understanding the role of climate change in intensifying specific weather and climate events such as extreme heat waves and heavy rainfall events.”

The report says “human actions still have the potential to determine the future course of climate,” and that carbon dioxide is the “main driver” of climate change.

“Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net zero CO2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate,” says Zhai.

With files from The Canadian Press and Brett Forester

More to come.

Online Producer / Ottawa

Before moving to become the APTN News social media producer, Mark was the executive producer for the news in eastern Canada. Before starting with APTN in 2009, Mark worked at CBC Radio and Television in Newfoundland and Labrador and Ottawa.