Climate change is accelerating at a higher rate than it has ever been before.
According to fresh scientific findings, the current rate of global warming is the fastest in 24,000 years. In the final days of COP26, this report is especially important.
A study led by the University of Arizona in the United States to reconstruct the Earth’s climate since the last ice age, 24,000 years ago, identifies the main drivers of climate change and the extent to which human activity has pushed the climate system beyond its limits, as well as demonstrating current “unprecedented” warming.
The study, published in the journal ‘Nature,’ confirms that rising greenhouse gas concentrations and retreating ice sheets are the main drivers of climate change since the last ice age, and suggests a general warming trend over the last 10,000 years, putting an end to a decade-long debate in the paleoclimatological community over whether this period was warmer or colder.
It goes on to say that the size and rate of warming over the last 150 years is significantly greater than the magnitude and rate of change over the previous 24,000 years. “This reconstruction suggests that current temperatures are unprecedented in the last 24,000 years, and that the rate of human-caused global warming is faster than anything we’ve seen in that time,” says Jessica Tierney, an associate professor of geosciences at the University of Arizona and a co-author of the study.
Tierney, who runs the lab where this research was done, is also known for her contributions to Intergovernmental Panel on Climate Change studies and congressional climate briefings. “The fact that we are so far outside the confines of what we may consider normal today is cause for anxiety and should come as a surprise to everyone,” says Matthew Osman, a postdoctoral researcher in geosciences at UArizona and the study’s lead author.
A search for ‘global temperature change since the last ice age’ on the internet yields an eight-year-old graph depicting global temperature change throughout time. Tierney continues, “Our team’s reconstruction enhances that curve by adding a spatial component.”
The researchers constructed maps of global temperature change over the last 24,000 years for every 200-year interval. “These maps are quite effective,” adds Osman. Anyone can use them to investigate how Earth’s temperatures have changed on a very personal level. Being able to visualize the 24,000-year history of temperatures in the precise spot where I’m sitting right now, or where I grew up, helped me grasp the gravity of present climate change.”
Reconstructing historic temperatures can be done in a variety of ways. To build a more full picture of the past, the team integrated two different data sets: marine sediment temperature measurements and climate computer simulations.
Researchers looked at the chemical traces of marine sediments to figure out what temperatures were like in the past. Paleoclimatologists can use the chemical of a long-dead animal’s shell to estimate the temperature of an area since temperature variations over time can impact the chemistry of the shell. They point out that it’s not a perfect thermometer, but it’s a start.
Computer-simulated climate models, on the other hand, provide temperature data based on scientists’ best understanding of the physics of the climate system, which isn’t perfect either. As a result, the team opted to combine the methodologies in a process known as data assimilation, which is also often employed in weather forecasting to take use of each other’s capabilities. “To forecast the weather, meteorologists start with a model that reflects the current weather and then update it using observations like temperature, pressure, humidity, wind direction, and so on,” Tierney explains.
This same concept was applied to prior weather by the team. “With this strategy, we can harness the relative benefits of each of these individual data sets to build observationally consistent, dynamic, and geographically full reconstructions of past climate change,” says Osman.
The team is now focusing on developing a mechanism to analyze climate change even further back in time. Tierney agrees that “we are enthusiastic to apply this approach to historical temperatures that were warmer than now” since “these epochs are effectively windows into our future as greenhouse gas emissions increase.”
Article Author Gerluxe