Key takeaways from the UN report on the climate crisis

Brandon Miller
By Brandon Miller, CNN
Updated 4:40 AM EDT, Mon August 9, 2021
Downtown Houston is seen behind the flooded Buffalo Bayou a few days after Hurricane Harvey came ashore in August 2017. The Category 4 storm caused historic flooding. It set a record for the most rainfall from a tropical cyclone in the continental United States, with 51 inches of rain recorded in areas of Texas. An estimated 27 trillion gallons of water fell over Texas and Louisiana during a six-day period.
Photos: Hurricane Harvey slams Texas
Paul Jordan Anderson/DoubleHorn Photography
Downtown Houston is seen behind the flooded Buffalo Bayou a few days after Hurricane Harvey came ashore in August 2017. The Category 4 storm caused historic flooding. It set a record for the most rainfall from a tropical cyclone in the continental United States, with 51 inches of rain recorded in areas of Texas. An estimated 27 trillion gallons of water fell over Texas and Louisiana during a six-day period.
NASA astronaut Jack Fischer photographed Hurricane Harvey from the International Space Station.
Photos: Hurricane Harvey slams Texas
Jack Fischer/NASA
NASA astronaut Jack Fischer photographed Hurricane Harvey from the International Space Station.
Steve Culver comforts his dog Otis in the hurricane aftermath. Harvey destroyed most of his home in Rockport while he and his wife were there.
Photos: Hurricane Harvey slams Texas
Joe Raedle/Getty Images
Steve Culver comforts his dog Otis in the hurricane aftermath. Harvey destroyed most of his home in Rockport while he and his wife were there.
Houston police officer Daryl Hudeck carries Catherine Pham and her 13-month-old son, Aiden, after rescuing them from floodwaters.
Photos: Hurricane Harvey slams Texas
David J. Phillip/AP
Houston police officer Daryl Hudeck carries Catherine Pham and her 13-month-old son, Aiden, after rescuing them from floodwaters.
A damaged home is seen in the Key Allegro neighborhood of Rockport.
Photos: Hurricane Harvey slams Texas
William Luther/San Antonio Express-News via ZUMA Wire
A damaged home is seen in the Key Allegro neighborhood of Rockport.
A car is submerged by floodwaters on a freeway near downtown Houston.
Photos: Hurricane Harvey slams Texas
Charlie Riedel/AP
A car is submerged by floodwaters on a freeway near downtown Houston.
Melani Zurawski cries while inspecting her home in Port Aransas, Texas.
Photos: Hurricane Harvey slams Texas
Nick Wagner/Austin American-Statesman via AP
Melani Zurawski cries while inspecting her home in Port Aransas, Texas.
A graveyard is flooded in Pearland, Texas.
Photos: Hurricane Harvey slams Texas
BRENDAN SMIALOWSKI/AFP/Getty Images
A graveyard is flooded in Pearland, Texas.
Soldiers with the National Guard patrol Rockport, looking for residents trapped in their homes.
Photos: Hurricane Harvey slams Texas
Timothy Fadek/Redux for CNN
Soldiers with the National Guard patrol Rockport, looking for residents trapped in their homes.
Evacuees are loaded onto a truck in Houston.
Photos: Hurricane Harvey slams Texas
BRENDAN SMIALOWSKI/AFP/Getty Images
Evacuees are loaded onto a truck in Houston.
People push a stalled pickup through a flooded street in Houston.
Photos: Hurricane Harvey slams Texas
Charlie Riedel/AP
People push a stalled pickup through a flooded street in Houston.
Rockport residents return to their destroyed home.
Photos: Hurricane Harvey slams Texas
Timothy Fadek/Redux for CNN
Rockport residents return to their destroyed home.
Rescue boats fill Tidwell Road in Houston as they help flood victims evacuate the area.
Photos: Hurricane Harvey slams Texas
David J. Phillip/AP
Rescue boats fill Tidwell Road in Houston as they help flood victims evacuate the area.
People wait to be rescued from their flooded home in Houston.
Photos: Hurricane Harvey slams Texas
Joe Raedle/Getty Images
People wait to be rescued from their flooded home in Houston.
Volunteers in Dallas organize items donated for hurricane victims.
Photos: Hurricane Harvey slams Texas
Tony Gutierrez/AP
Volunteers in Dallas organize items donated for hurricane victims.
When Harvey slammed the Texas coast and flooded much of Houston, <a href="https://www.cnn.com/interactive/2017/08/us/hurricane-harvey-cnnphotos/" target="_blank">volunteers sprang into action.</a> Some came from as far away as the Florida Everglades, boats in tow, ready to rescue people trapped in their homes.
Photos: Hurricane Harvey slams Texas
Timothy Fadek/Redux for CNN
When Harvey slammed the Texas coast and flooded much of Houston, volunteers sprang into action. Some came from as far away as the Florida Everglades, boats in tow, ready to rescue people trapped in their homes.
Larry Koser Jr. and his son Matthew look for important papers and heirlooms inside a flooded home in Houston.
Photos: Hurricane Harvey slams Texas
Erich Schlegel/Getty Images
Larry Koser Jr. and his son Matthew look for important papers and heirlooms inside a flooded home in Houston.
Members of the National Guard rest at a furniture store in Richmond, Texas.
Photos: Hurricane Harvey slams Texas
Alyssa Schukar/The New York Times/Redux Pictures
Members of the National Guard rest at a furniture store in Richmond, Texas.
Volunteer rescue workers help a woman from her flooded home in Port Arthur, Texas.
Photos: Hurricane Harvey slams Texas
Joe Raedle/Getty Images
Volunteer rescue workers help a woman from her flooded home in Port Arthur, Texas.
This aerial photo shows flooded residential neighborhoods in Houston.
Photos: Hurricane Harvey slams Texas
Marcus Yam/Los Angeles Times/Getty Images
This aerial photo shows flooded residential neighborhoods in Houston.
Tammy Dominguez and her husband, Christopher, sleep on cots at the George R. Brown Convention Center, where thousands of people were taking shelter in Houston.
Photos: Hurricane Harvey slams Texas
Michael Ciaglo/Houston Chronicle/AP
Tammy Dominguez and her husband, Christopher, sleep on cots at the George R. Brown Convention Center, where thousands of people were taking shelter in Houston.
An elderly patient waits to be rescued from the Gulf Health Care Center in Port Arthur. The facility was evacuated with the help of first responders and volunteers.
Photos: Hurricane Harvey slams Texas
Nick Oza/USA Today Network/Sipa USA
An elderly patient waits to be rescued from the Gulf Health Care Center in Port Arthur. The facility was evacuated with the help of first responders and volunteers.
CNN  — 

Monday’s report from the United Nations’ Intergovernmental Panel on Climate Change (IPCC) represents the most comprehensive and conclusive “state of the science” on the climate crisis: why it is happening, how it is impacting every region of the planet, how much worse things are set to get and what must be done to avoid the worst consequences.

UN Secretary-General António Guterres called the report “a code red for humanity,” noting that “global heating is affecting every region on Earth, with many of the changes becoming irreversible.”

The report is around 3,500 pages, represents years of research on the topic, was authored by more than 200 scientists from over 60 countries and cites more than 14,000 individual studies.

Humans are unequivocally warming the planet

  • This report goes farther than any previous IPCC climate report in placing the blame for global warming squarely on human greenhouse gas emissions. It is no longer a question of “natural versus human-caused” climate change. Society’s reliance on fossil fuels is the reason the planet has already warmed 1.2 degrees Celsius – every bit of it through the emission of greenhouse gases such as carbon dioxide and methane.
  • The warming is happening even faster than scientists previously thought, and the latest projections have us reaching or exceeding 1.5 degrees – a key threshold scientists say is critical to stay below – within the next decade or two.

The only way to stop the warming is to end greenhouse gas emissions: The longer it takes, the hotter it gets

  • Just as the the report clearly blames carbon pollution for the rising temperatures, it is also clear that the only way to slow down and eventually reverse the warming is to reduce greenhouse gas emissions to zero.
  • Avoiding 1.5 degrees of warming is all but impossible, but we can still keep warming around that critical threshold and avoid the worsening impacts that come from approaching and passing 2 degrees of warming.
  • Avoiding those impacts will take significant cuts to greenhouse gas emissions starting immediately. If emissions continue to increase, the world will top 2 degrees of warming – possibly before 2050 – and reach 3 degrees before the end of the century.
Firefighters battle a wildfire near Avila, Spain, on August 16.
Photos: Europe battles wildfires amid scorching heat waves
Cesar Manso/AFP/Getty Images
Firefighters battle a wildfire near Avila, Spain, on August 16.
A helicopter drops water as a wildfire burns in the village of Navalmoral, Spain, on August 16.
Photos: Europe battles wildfires amid scorching heat waves
Juan Medina/Reuters
A helicopter drops water as a wildfire burns in the village of Navalmoral, Spain, on August 16.
A man works to douse a fire in Montalto, Italy, on August 12.
Photos: Europe battles wildfires amid scorching heat waves
Vincenzo Circosta/Medialys Image/Shutterstock
A man works to douse a fire in Montalto, Italy, on August 12.
Forest fires rage on the Greek island of Euboea on August 11.
Photos: Europe battles wildfires amid scorching heat waves
Handout/Latin America News Agency/Reuters
Forest fires rage on the Greek island of Euboea on August 11.
This aerial photo shows a wildfire-affected area in Mugla, Turkey, on August 11.
Photos: Europe battles wildfires amid scorching heat waves
Omer Urer/Anadolu Agency/Getty Images
This aerial photo shows a wildfire-affected area in Mugla, Turkey, on August 11.
Remains of an 18th-century Orthodox church are seen on August 10, after a fire on the Greek island of Evia.
Photos: Europe battles wildfires amid scorching heat waves
Milos Bicanski/Getty Images
Remains of an 18th-century Orthodox church are seen on August 10, after a fire on the Greek island of Evia.
Local youths and volunteers gather in a field and wait to support firefighters during a wildfire on August 9, close to the village of Kamatriades on the Greek island of Evia.
Photos: Europe battles wildfires amid scorching heat waves
Angelos Tzortzinis/AFP/Getty Images
Local youths and volunteers gather in a field and wait to support firefighters during a wildfire on August 9, close to the village of Kamatriades on the Greek island of Evia.
People sleep in a car near the beach in Pefki village as wildfires rage on the island of Evia on August 8.
Photos: Europe battles wildfires amid scorching heat waves
Angelos Tzortzinis/AFP/Getty Images
People sleep in a car near the beach in Pefki village as wildfires rage on the island of Evia on August 8.
A resident reacts as a wildfire approaches her house in the Greek village of Gouves, on the island of Evia, on August 8.
Photos: Europe battles wildfires amid scorching heat waves
Konstantinos Tsakalidis/Bloomberg/Getty Images
A resident reacts as a wildfire approaches her house in the Greek village of Gouves, on the island of Evia, on August 8.
A house in Pefkofito, Greece, is destroyed on August 7.
Photos: Europe battles wildfires amid scorching heat waves
Angelos Tzortzinis/AFP/Getty Images
A house in Pefkofito, Greece, is destroyed on August 7.
A firefighter washes his face in the Milas area of Mugla, Turkey, on August 7.
Photos: Europe battles wildfires amid scorching heat waves
Emre Tazegul/AP
A firefighter washes his face in the Milas area of Mugla, Turkey, on August 7.
People are evacuated on a ferry as a wildfire burns in Limni, Greece, on August 6.
Photos: Europe battles wildfires amid scorching heat waves
Nicolas Economou/Reuters
People are evacuated on a ferry as a wildfire burns in Limni, Greece, on August 6.
A satellite photo shows smoke rising from fires on the island of Evia, Greece, on August 5.
Photos: Europe battles wildfires amid scorching heat waves
Planet Labs Inc./AP
A satellite photo shows smoke rising from fires on the island of Evia, Greece, on August 5.
Firefighters try to extinguish a wildfire near the town of Olympia, Greece, on August 5.
Photos: Europe battles wildfires amid scorching heat waves
Giannis Spyrounis/ilialive.gr/AP
Firefighters try to extinguish a wildfire near the town of Olympia, Greece, on August 5.
Residents react during a wildfire near Olympia on August 5.
Photos: Europe battles wildfires amid scorching heat waves
Giannis Spyrounis/AP
Residents react during a wildfire near Olympia on August 5.
The grounds of a burnt hotel are seen in Lalas village, near Olympia, on August 5.
Photos: Europe battles wildfires amid scorching heat waves
Giannis Spyrounis/ilialive.gr/AP
The grounds of a burnt hotel are seen in Lalas village, near Olympia, on August 5.
People move belongings to safety as a forest fire rages in a wooded area north of Athens, Greece, on August 5.
Photos: Europe battles wildfires amid scorching heat waves
Angelos Tzortzinis/picture alliance/Getty Images
People move belongings to safety as a forest fire rages in a wooded area north of Athens, Greece, on August 5.
A wildfire approaches the Olympic Academy in Olympia, Greece, on August 4.
Photos: Europe battles wildfires amid scorching heat waves
Giannis Spyrounis/ilialive.gr/AP
A wildfire approaches the Olympic Academy in Olympia, Greece, on August 4.
The remnants of a destroyed house are seen in the Varibobi area of northern Athens on August 4.
Photos: Europe battles wildfires amid scorching heat waves
Thanassis Stavrakis/AP
The remnants of a destroyed house are seen in the Varibobi area of northern Athens on August 4.
Onlookers view the smoke from the wildfires blanketing Athens' Acropolis on August 4.
Photos: Europe battles wildfires amid scorching heat waves
Louisa Gouliamaki/AFP/Getty Images
Onlookers view the smoke from the wildfires blanketing Athens' Acropolis on August 4.
A charred area of Mugla, Turkey, after a forest fire on August 3.
Photos: Europe battles wildfires amid scorching heat waves
Yasin Akgul/AFP/Getty Images
A charred area of Mugla, Turkey, after a forest fire on August 3.
Smoke and flames rise over the village of Limni on the Greek island of Evia.
Photos: Europe battles wildfires amid scorching heat waves
Michael Pappas/AP
Smoke and flames rise over the village of Limni on the Greek island of Evia.
Firefighters work as a house burns in the Adames area of northern Athens on August 3.
Photos: Europe battles wildfires amid scorching heat waves
Michael Varaklas/AP
Firefighters work as a house burns in the Adames area of northern Athens on August 3.
A woman pours water over a baby's head at a fountain in Skopje, North Macedonia, as temperatures reached over 40 degrees Celsius (104 degrees Fahrenheit) on August 2.
Photos: Europe battles wildfires amid scorching heat waves
Georgi Licovslki/EPA-EFE/Shutterstock
A woman pours water over a baby's head at a fountain in Skopje, North Macedonia, as temperatures reached over 40 degrees Celsius (104 degrees Fahrenheit) on August 2.
A man leads sheep away from an advancing fire in Mugla, Turkey, on August 2.
Photos: Europe battles wildfires amid scorching heat waves
Yasin Akgul/AFP/Getty Images
A man leads sheep away from an advancing fire in Mugla, Turkey, on August 2.
People watch an advancing fire that rages around the Cokertme village near Bodrum, Turkey, on August 2.
Photos: Europe battles wildfires amid scorching heat waves
Emre Tazegul/AP
People watch an advancing fire that rages around the Cokertme village near Bodrum, Turkey, on August 2.
Local residents watch as a Greek army helicopter collects water to tackle a wildfire near the village of Lambiri, Greece, on August 1.
Photos: Europe battles wildfires amid scorching heat waves
Milos Bicanski/Getty Images
Local residents watch as a Greek army helicopter collects water to tackle a wildfire near the village of Lambiri, Greece, on August 1.
A handout photo from the Italian National Fire Brigade shows an aerial view of a fire in the Pineta Dannunziana reserve in Pescara, Italy, on August 1.
Photos: Europe battles wildfires amid scorching heat waves
Handout/Vigili del Fuoco/EPA-EFE/Shutterstock
A handout photo from the Italian National Fire Brigade shows an aerial view of a fire in the Pineta Dannunziana reserve in Pescara, Italy, on August 1.
A man surveys a fire at Le Capannine beach in the Sicilian town of Catania, Italy, on July 30.
Photos: Europe battles wildfires amid scorching heat waves
Roberto Viglianisi/Reuters
A man surveys a fire at Le Capannine beach in the Sicilian town of Catania, Italy, on July 30.
Firefighters battle a massive wildfire that engulfed a Mediterranean resort region on Turkey's southern coast near the town of Manavgat on July 29.
Photos: Europe battles wildfires amid scorching heat waves
Ilyas Akengin/AFP/Getty Images
Firefighters battle a massive wildfire that engulfed a Mediterranean resort region on Turkey's southern coast near the town of Manavgat on July 29.
A firefighter talks to his colleague as they work to put out fires in Cuglieri, on the Italian island of Sardinia, on July 26.
Photos: Europe battles wildfires amid scorching heat waves
Alessandro Tocco/LaPresse/AP
A firefighter talks to his colleague as they work to put out fires in Cuglieri, on the Italian island of Sardinia, on July 26.
A firefighting helicopter passes in front of a cloud of smoke from a forest fire near Spathovouni village, southwest of Athens, Greece, on July 23.
Photos: Europe battles wildfires amid scorching heat waves
Valerie Gache/AP
A firefighting helicopter passes in front of a cloud of smoke from a forest fire near Spathovouni village, southwest of Athens, Greece, on July 23.

Climate impacts are severe in every region of the planet, and will worsen with every fraction of a degree of warming

Here are are some specific impacts and what the report has to say about them.

  • Heat waves – Extreme heat waves, such as the deadly one that occurred in the Pacific Northwest and Canada earlier this summer, are already about five times more likely to occur with our current warming of just over 1 degree Celsius. At 2 degrees warming, this frequency increases to 14 times as likely to occur. Heat waves are getting hotter, and with 2 degrees of warming, the hottest temperatures would reach nearly 3 degrees Celsius (5 degrees Fahrenheit) higher than previous heat waves.
  • Droughts – Climate change is increasing the frequency and severity of droughts – such as the current drought plaguing the Western United States. Severe droughts that used to occur an average of once per decade are now occurring about 70% more frequently. If warming continues to 2 degrees, these droughts will occur between two and three times as often.
  • Flooding – Climate change is intensifying the water cycle on both sides. While more intense evaporation will lead to more droughts, warmer air can hold more water vapor to produce extreme rainfall (as we have seen play out dramatically in Western Europe and China this summer). On average, the frequency of heavy downpours has already increased by about 30% and they contain about 7% more water.
  • Hurricanes – Hurricanes are growing stronger and producing more rain as global temperatures increase. It has already been observed that, globally, a higher percentage of storms are reaching the highest categories (categories 3, 4 and 5) in recent decades. This is expected to continue as temperatures climb.
  • Sea level rise – Sea level is rising around the world, and the rate is increasing. This is worsening high-tide flooding and storm surge. By 2100, once-in-a-century coastal flood events will occur at least once per year at more than half of coastlines across the world, the report said.
  • Weather whiplash – Climate change is not just increasing the severity of extreme weather, it is interrupting the natural patterns, leading to “weather whiplash” – wild swings between dry and wet extremes. This has been experienced recently in California, with “atmospheric rivers” causing destructive floods one year and extreme drought causing water shortages the next.
<strong>South Georgia -- </strong>Adult king penguins in St Andrews Bay, South Georgia. The colony has grown substantially in the past century, with hundreds of thousands of breeding pairs frequenting the bay every year. Glacial retreat has exposed new land for these seabirds, which do not nest on ice and prefer to moult their feathers in freshwater streams.
Photos: The effects of climate change around the world
REDA&CO/Universal Images Group Editorial/Universal Images Group via Getty
South Georgia -- Adult king penguins in St Andrews Bay, South Georgia. The colony has grown substantially in the past century, with hundreds of thousands of breeding pairs frequenting the bay every year. Glacial retreat has exposed new land for these seabirds, which do not nest on ice and prefer to moult their feathers in freshwater streams.
In Ryrkaypiy, a village in Russia's Far Eastern region of Chukotka, polar bears come in close contact with humans in December 2019. Higher than average temperatures driving coastal ice melt prevented over 60 bears from migrating, forcing them to approach the village in search of food.
Photos: The effects of climate change around the world
TASS/TASS/Maxim Deminov/TASS
Russia —
In Ryrkaypiy, a village in Russia's Far Eastern region of Chukotka, polar bears come in close contact with humans in December 2019. Higher than average temperatures driving coastal ice melt prevented over 60 bears from migrating, forcing them to approach the village in search of food.
A flooded street in Miami Beach in September 2015. The flood was caused by a combination of seasonal high tides and what many believe is a rise in sea levels due to climate change. Miami Beach has already built <a href="http://edition.cnn.com/2016/02/29/opinions/sutter-miami-beach-survive-climate/index.html">miles of seawalls</a> and has embarked on a five-year, $400 million stormwater pump program to keep the ocean waters from inundating the city.
Photos: The effects of climate change on the world
Joe Raedle/Getty Images North America/Getty Images
Florida —
A flooded street in Miami Beach in September 2015. The flood was caused by a combination of seasonal high tides and what many believe is a rise in sea levels due to climate change. Miami Beach has already built miles of seawalls and has embarked on a five-year, $400 million stormwater pump program to keep the ocean waters from inundating the city.
Sea water collects in front of a home in Tangier, Virginia, in May 2017. Tangier Island in Chesapeake Bay has lost two-thirds of its landmass since 1850. Now, the 1.2 square mile island is suffering from floods and erosion and is slowly sinking. A <a href="https://www.nature.com/articles/srep17890" target="_blank" target="_blank">paper</a> published in the journal Scientific Reports states that "the citizens of Tangier may become among the first climate change refugees in the continental USA."
Photos: The effects of climate change on the world
JIM WATSON/AFP/AFP/Getty Images
Virginia —
Sea water collects in front of a home in Tangier, Virginia, in May 2017. Tangier Island in Chesapeake Bay has lost two-thirds of its landmass since 1850. Now, the 1.2 square mile island is suffering from floods and erosion and is slowly sinking. A paper published in the journal Scientific Reports states that "the citizens of Tangier may become among the first climate change refugees in the continental USA."
The Pasterze glacier is Austria's largest and it's shrinking rapidly: the sign on the trail indicates where the foot of the glacier reached in 2015, a year before this photo was taken. The European Environmental Agency <a href="https://www.eea.europa.eu/data-and-maps/indicators/glaciers-2/assessment" target="_blank" target="_blank">predicts</a> the volume of European glaciers will decline by between 22 percent and 89 percent by 2100, depending on the future intensity of greenhouse gases.
Photos: The effects of climate change on the world
Sean Gallup/Getty Images Europe/Getty Images
Austria —
The Pasterze glacier is Austria's largest and it's shrinking rapidly: the sign on the trail indicates where the foot of the glacier reached in 2015, a year before this photo was taken. The European Environmental Agency predicts the volume of European glaciers will decline by between 22 percent and 89 percent by 2100, depending on the future intensity of greenhouse gases.
A NASA research aircraft flies over retreating glaciers on the Upper Baffin Bay coast of Greenland. Scientists say the Arctic is one of the regions hit hardest by climate change.
Photos: The effects of climate change on the world
Mario Tama/Getty Images
Greenland —
A NASA research aircraft flies over retreating glaciers on the Upper Baffin Bay coast of Greenland. Scientists say the Arctic is one of the regions hit hardest by climate change.
A wooden pole that had been driven into the ice the year before now stands exposed as the Aletsch glacier melts and sinks at a rate of about 10-13 meters per year near Bettmeralp, Switzerland.
Photos: The effects of climate change on the world
Sean Gallup/Getty Images Europe/Getty Images
Switzerland —
A wooden pole that had been driven into the ice the year before now stands exposed as the Aletsch glacier melts and sinks at a rate of about 10-13 meters per year near Bettmeralp, Switzerland.
In the Mississippi Delta, trees are withering away because of rising saltwater, creating "<a href="http://edition.cnn.com/2017/04/20/us/louisiana-climate-change-skeptics/index.html">Ghost Forests</a>."
Photos: The effects of climate change on the world
John Rubenstahl/CNN Air
Louisiana —
In the Mississippi Delta, trees are withering away because of rising saltwater, creating "Ghost Forests."
A street is flooded in Sun Valley, Southern California in February 2017. Powerful storms have swept Southern California after years of severe drought, in a "drought-to-deluge" cycle that some <a href="http://www.latimes.com/local/lanow/la-me-record-rains-20170410-story.html" target="_blank" target="_blank">believe</a> is consistent with the consequences of global warming.
Photos: The effects of climate change on the world
David McNew/Getty Images North America/Getty Images
California —
A street is flooded in Sun Valley, Southern California in February 2017. Powerful storms have swept Southern California after years of severe drought, in a "drought-to-deluge" cycle that some believe is consistent with the consequences of global warming.
The carcass of a dead cow lies in the Black Umfolozi River, dry from the effects of a severe drought, in Nongoma district north west from Durban, in November 2015. South Africa ranks as the 30th driest country in the world and is considered a water-scarce region. A highly variable climate causes uneven distribution of rainfall, making droughts even more extreme.
Photos: The effects of climate change on the world
MUJAHID SAFODIEN/AFP/AFP/Getty Images
South Africa —
The carcass of a dead cow lies in the Black Umfolozi River, dry from the effects of a severe drought, in Nongoma district north west from Durban, in November 2015. South Africa ranks as the 30th driest country in the world and is considered a water-scarce region. A highly variable climate causes uneven distribution of rainfall, making droughts even more extreme.
A gigantic cloud of dust known as "Haboob" advances over Sudan's capital, Khartoum. Moving like a thick wall, it carries sand and dust burying homes, while increasing evaporation in a region that's struggling to preserve water supplies. <a href="http://edition.cnn.com/2016/12/07/africa/sudan-climate-change/index.html">Experts say</a> that without quick intervention, parts of the African country -- one of the most vulnerable in the world -- could become uninhabitable as a result of climate change.
Photos: The effects of climate change on the world
AFP/Getty Images
Sudan —
A gigantic cloud of dust known as "Haboob" advances over Sudan's capital, Khartoum. Moving like a thick wall, it carries sand and dust burying homes, while increasing evaporation in a region that's struggling to preserve water supplies. Experts say that without quick intervention, parts of the African country -- one of the most vulnerable in the world -- could become uninhabitable as a result of climate change.
Low tide reveals the extent of accelerated erosion shown by the amount of exposed beach rocks on Maafushi beach in the Maldives. This is the world's lowest-lying country, with no part lying more than six feet above sea level. The island nation's future is under threat from anticipated global sea level rise, with many of its islands already suffering from coastal erosion.
Photos: The effects of climate change on the world
Aishath Adam/Getty Images AsiaPac/Getty Images
Maldives —
Low tide reveals the extent of accelerated erosion shown by the amount of exposed beach rocks on Maafushi beach in the Maldives. This is the world's lowest-lying country, with no part lying more than six feet above sea level. The island nation's future is under threat from anticipated global sea level rise, with many of its islands already suffering from coastal erosion.
Los Glaciares National Park, part of the third largest ice field in the world, on November 27, 2015 in Santa Cruz Province, Argentina. The majority of the almost 50 large glaciers in the park have been retreating during the past 50 years due to warming temperatures, according to the European Space Agency (ESA).
Photos: The effects of climate change on the world
Mario Tama/Getty Images South America/Getty Images
Argentina —
Los Glaciares National Park, part of the third largest ice field in the world, on November 27, 2015 in Santa Cruz Province, Argentina. The majority of the almost 50 large glaciers in the park have been retreating during the past 50 years due to warming temperatures, according to the European Space Agency (ESA).
A boy from the remote Turkana tribe in Northern Kenya walks across a dried up river near Lodwar, Kenya. Millions of people across Africa are facing a critical shortage of water and food, a situation made worse by climate change.
Photos: The effects of climate change on the world
Christopher Furlong/Getty Images Europe/Getty Images
Kenya —
A boy from the remote Turkana tribe in Northern Kenya walks across a dried up river near Lodwar, Kenya. Millions of people across Africa are facing a critical shortage of water and food, a situation made worse by climate change.
An Indian farmer in a dried up cotton field in the southern Indian state of Telangana, in April 2016. Much of India is <a href="http://edition.cnn.com/2016/05/04/asia/gallery/india-drought-crisis/index.html">reeling</a> from a heat wave and severe drought conditions that have decimated crops, killed livestock and left at least 330 million people without enough water for their daily needs.
Photos: The effects of climate change on the world
NOAH SEELAM/AFP/AFP/Getty Images
India —
An Indian farmer in a dried up cotton field in the southern Indian state of Telangana, in April 2016. Much of India is reeling from a heat wave and severe drought conditions that have decimated crops, killed livestock and left at least 330 million people without enough water for their daily needs.
Strawberries lost due to a fungus that experts report is caused by climate change in La Tigra, Honduras, in September 2016. According to Germanwatch's Global Climate Risk Index, Honduras ranks among the countries most affected by climate change.
Photos: The effects of climate change on the world
ORLANDO SIERRA/AFP/AFP/Getty Images
Honduras —
Strawberries lost due to a fungus that experts report is caused by climate change in La Tigra, Honduras, in September 2016. According to Germanwatch's Global Climate Risk Index, Honduras ranks among the countries most affected by climate change.

Some changes are irreversible, even under the lowest emissions scenarios

  • Warming that has already occurred has triggered changes that will persist even if the emissions stop and temperatures stabilize.
  • Ice sheets will continue melting for hundreds to thousands of years, according to the report, which will cause sea levels to rise well beyond 2100 and stay higher for millennia.
  • Sea levels are expected to rise 2 to 3 meters by 2300 even if warming is kept below 2 degrees, but could reach 5 to 7 meters or higher if warming continues unabated.

Atmospheric methane is skyrocketing

  • This report points to another villain in the climate crisis — methane — an invisible gas that contains more than 80 times the planet-warming power of carbon dioxide in the short term.
  • Newer data shows that methane in the atmosphere is skyrocketing and is currently the highest it’s been in 800,000 years, largely because of a combination of natural gas leaks and unsustainable agriculture and cattle farming.
  • Considering its massive warming potential and its shorter lifetime in the atmosphere compared to carbon dioxide, controlling methane could significantly lessen global warming in the coming decades.

IPCC reports, while long on science and exhaustive in scope and detail, contain precious little in suggesting policy to remedy the climate crisis. This report, for example, is purely the scientific facts and forecasts for the future.

Major IPCC reports coming next year will go into more detail on specific impacts and ways to mitigate them, but before then global leaders will meet at a UN-led climate conference in November, in what is being billed as the most consequential climate policy meeting since the Paris Agreement was signed in 2015.

“As today’s report makes clear, there is no time for delay and no room for excuses,” the UN secretary-general declared this morning, as he implored government leaders to ensure COP26 is a success in order to “avert climate catastrophe.”