Heat wave
The chance the ongoing spate of worldwide temperature spikes might be flukes and not man-made was debunked by a new study that shows random change isn't the culprit in climate change.
In a newly published study, Erich Fischer and Reto Knutti at the Institute for Atmospheric and Climate Science in Zurich, Switzerland, said that as climate change worsens by the 2050s, the percentage of extremely hot days being caused by man-made greenhouse gases will exceed 95 percent.
The scientists also said 18 percent of extreme rain events are caused by climate change. This percentage is expected to rise to 39 percent if the world warms an additional 2 degrees Fahrenheit. Triggering this rise in temperatures will be greenhouse gases, mostly carbon dioxide from the burning of coal, oil and gas.
Fischer, the lead author and a climate scientist, and Knutti examined the hottest of hot days on Earth or the hottest one-tenth of one percent.
Using 25 different computer models, they simulated a world without man-made greenhouse gas emissions and found these hot days occurred once every three years.
They then estimated how many times these hot days occur with the current level of greenhouse gases. They found the number rose to four days every three years. So three of the four are man-made, the researchers said.
"A 1-in-10,000 day heat event is something that's only expected to happen every 30 years. But in a global-warming world, it's turned into a 4-in-10,000 day event. Three of those hot days -- or 75 per cent -- would never have happened if global warming wasn't around", said Fischer.
A scenario that sees a rise in greenhouse gases using current pollution trends to simulate a world by 2050 resulted in a world with 26 superhot days or "almost a whole month", according to Fischer.
If man-made greenhouse gas emissions continue at current pace, all continents will be able to blame at least 93 percent of super hot days on humans by the 2050s.
While climate change isn't the only cause of extreme weather, it's increasingly tipping the scales in its favor.
"Some people argue that these things have happened before", Fisher noted. "Well, yes, they have. But they had been far less frequent."
Fischer and Knutti also looked at what would happen if the climate warmed by 2 °C, a threshold many scientists warn would be dangerous to exceed. They said in a 2 °C world, climate change would be responsible for four of every 10 extreme rainstorms, according to New Scientist.
