The earth is warming at an unprecedented rate in the last 2,000 years as a result of modern society’s continuous reliance on fossil fuels.
and its consequences are already being felt as record droughts, wildfires, and floods wreak havoc on communities around the world.
according to a groundbreaking United Nations assessment on the state of climate research.
According to the UN’s Intergovernmental Panel on Climate Change (IPCC), if greenhouse-gas emissions continue, things will become worse.
But it also makes obvious that humanity’s actions now will have a significant impact on the planet’s future.
“The evidence is all around us: if we don’t act, things are going to grow a lot worse,” says Xuebin Zhang.
a climatologist at Environment Canada in Toronto who served as the report’s coordinating main author on August 9th.
Over 200 experts worked on the report for several years before it was accepted by 195 nations during a virtual meeting last week.
The study is the first of three that will examine climate change and measures to minimize and adapt to it.
The paper, which is part of the IPCC’s sixth climate assessment since 1990, arrives just over three months before the next big global climate meeting, which will take place in Glasgow, Scotland.
Governments will be able to make pledges to change course and reduce their emissions at the conference.
If global emissions are reduced to zero by the middle of the century, as many governments have pledged in the last year, the world will be a better place.
Then, according to Valérie Masson-Delmotte, the world can meet the 2015 Paris Agreement’s aim of limiting global warming to 1.5 degrees Celsius throughout the twenty-first century.
co-chair of the physical-science working group that produced the current report and a climatologist at the Climate and Environmental Sciences Laboratory in Gif-sur-Yvette, France.
“Our decisions now will determine the climate we will experience in the future,” she says.
The global surface temperature has risen by roughly 1.1 degrees Celsius from 1850–1900, reaching a level not seen since before the last ice age, some 125,000 years ago.
This is only one of the frank realities in a summary released alongside the IPCC report and aimed at policymakers.
The overall study emphasizes efforts to determine how much higher temperatures will rise if current emissions levels are maintained.
Climate experts’ most confident estimates for the twenty-first century are included in this report.
Climate sensitivity is a fundamental parameter that researchers use to make estimates.
a metric for how much long-term warming would be projected on Earth if atmospheric carbon dioxide levels were doubled from pre-industrial levels.
Even though the IPCC’s best estimate remains at 3 degrees Celsius, the study lessens the uncertainty surrounding that figure.
Using information such as present and ancient climate records, the likely range has been narrowed to 2.5–4 °C.
In the IPCC’s most recent climate assessment, released in 2013, the greater range for sensitivity was given as 1.5–4.5 °C.
Climate sensitivity is narrowing, which gives scientists more confidence in their estimates of what will happen on Earth under various scenarios.
According to the IPCC study, average global temperatures will climb 2.1–3.5 °C in a moderate emissions scenario with little change to today’s global growth trends.
This is significantly beyond the 1.5–2 °C target set by the countries that signed the Paris Climate Agreement in 2015.
Even if governments actively reduce greenhouse-gas emissions, the paper predicts that global temperatures will likely exceed 1.5 degrees Celsius in the coming years.
before reverting to below that level by the end of the century.
“Is it still possible to keep global warming below 1.5 degrees Celsius? “The answer is yes,” says Maisa Rojas, director of the University of Chile’s Centre for Climate and Resilience Research in Santiago and a coordinating lead author on the paper.
“However, reducing global warming to 1.5 degrees Celsius will be impossible to achieve unless all greenhouse gases are reduced immediately, rapidly, and on a vast scale.”
Climate change has produced a dizzying array of effects on Earth, which are already visible from pole to pole, according to the paper.
During the late summer, sea ice coverage in the Arctic was lower in the last decade than it had been in at least 1,000 years.
The current global glacier retreat is unprecedented in at least 2,000 years.
Furthermore, seas are warming at a rate not witnessed since the end of the last ice age 11,000 years ago.
Aside from these sobering statistics, the IPCC report highlights some of the most significant scientific advances in understanding the regional impacts of climate change, such as where extreme heat, precipitation, and drought have wreaked the most havoc.
Extreme drought, for example, has wreaked havoc on numerous parts of the globe, with particularly severe consequences in the Mediterranean and southwest Africa.
Extreme weather occurrences will grow more severe as temperatures rise in the future, according to Zhang.
According to the report, if Earth’s temperature rises 2 degrees Celsius above preindustrial levels, extreme temperature events that occurred once every 50 years in the past will likely occur every four years.
More compound occurrences, like heat waves and long-term droughts, should be expected over the world.
“We will not be hit by just one item; we will be hit by numerous things at the same time,” Zhang predicts.
CHANGES THAT ARE IMPOSSIBLE TO REVERSE
According to the report, the effects of global warming on bodies like glaciers, ice sheets, and oceans will be felt for centuries, if not millennia.
They are still adjusting to the current level of warming, let alone future temperature increases.
Even if global warming is limited to 1.5 degrees Celsius, sea levels are expected to increase by 2–3 meters over the next 2,000 years.
with a 2°C increase, and up to 6 meters with a 2°C increase, affecting entire coastlines currently inhabited by hundreds of millions of people.
Some of the most catastrophic climate impacts, such as ice-sheet collapse, significant forest loss, or a sudden change in ocean circulation, cannot be ruled out, according to the paper.
Especially in scenarios involving high emissions and severe warming by the end of the century.
However, it points out that the largest unknown in all climate-change estimates is how humanity will respond.
For three decades, the IPCC has been warning about the dangers of global warming.
Governments, on the other hand, have yet to take the steps necessary to transition to renewable energy sources and reduce greenhouse gas emissions.
However, Zhang believes that things are about to change, if only because people all around the world are beginning to see the effects of climate change.
“Climate change is real, and people are feeling it,” Zhang says. “The paper merely serves as scientific confirmation to the broader population that, sure, what you believe is correct.”
However, the IPCC report also asserts something even more crucial: many of climate change’s most serious consequences can still be avoided if robust action is taken now.
According to Rojas, every degree of warming matters. She says, “That is a very powerful thought.” “We hold the key to the future.”