How climate change is causing extreme heat around the world
Climate change is driving dangerous heat waves in the Northern Hemisphere this week and will continue to cause dangerous weather for decades, according to research.
"We are now suffering from a global heat wave," said Christiana Figueres, former head of the UN climate agency.
Read below how climate change is pushing heat to extremes.
How is climate change driving heat?
As the continued burning of fossil fuels releases more carbon emissions into the hemisphere, the air can collect more heat from the sun, and thus drive the increase in global average temperature over time.
The average global temperature has already risen by nearly 1.3 degrees Celsius since the Industrial Revolution began, when Western countries started burning coal and other fossil fuels.
This increase means that climate change is making heat waves hotter than they would have been without atmospheric warming. They are also becoming more common in general – and more dangerous as a result.
Each heat wave "has become much more likely and hotter than it would have been as a result of human-induced climate change," UCLA scientist Daniel Swain said earlier this month.
"At this time, making such a statement is a small thing, because there is too much evidence to support this," he said.
What is the impact of climate change?
In addition to global warming, there are other factors and conditions that can affect heat waves. Climatic phenomena such as El Nino or La Nina can have a great impact, along with the wind circulation system.
Land cover can also play a role, because dark surfaces and environments where there are constructions become warmer than white surfaces or natural environments such as forests or wetlands.
To understand exactly how much climate change has affected a particular heat wave, scientists conduct "attribution research."
They have conducted hundreds of such studies in the past decade by running computer simulations to compare today's weather systems with what the weather would have been like if humans had not changed the chemistry of the atmosphere over the past century.
For example, scientists at the World Weather Report found that the dangerous heat in South Asia in April was likely due to climate change. During a heatwave in the northeastern Indian city of Kolkata, the temperature reached 46 degrees Celsius - 10 degrees above the seasonal average.
What can we expect in the near future?
Even if carbon emissions were to stop today, the world has released enough carbon to guarantee that climate change will continue to affect rising temperatures for decades.
The world must cut emissions by half from 1995 levels by 2030 – and to zero by 2050 – to have a chance of keeping average temperature increases to about 1.5 degrees below the pre-industrial average, according to scientists from the Intergovernmental Panel on Climate Change.
However, global emissions have only increased since 1995. The world is on track to average 2.7 degrees by 2100, which would exceed the 1.5 threshold beyond which scientists have predicted catastrophic and irreversible climate impacts.
The fact that millions of people "in the United States are suffering from unprecedented heat waves is an indication that we have not yet addressed the worst of climate change," Figueres told Reuters on Thursday./REL