Dead trees stand on the beach and in the ocean at "The Boneyard," created by beach erosion and fierce storms, in Hunting Island State Park on Hunting Island, S.C., in the United States

Seemingly small shifts in global temperatures have huge consequences for the planet

The year 2021 was once again one of the hottest on record. And what may seem like a slight temperature increase has actually caused devastating effects across the globe, with natural disasters becoming stronger and deadlier.

The World

Dead trees stand on the beach and in the ocean at "The Boneyard," created by beach erosion and fierce storms, in Hunting Island State Park on Hunting Island, South Carolina, in the United States, Oct. 30, 2021.

Rebecca Blackwell/AP/File photo

Last year was once again recorded as one of the hottest on record.

NASA said that 2021 tied for the sixth-hottest year yet. And the National Oceanic and Atmospheric Administration (NOAA) said it owns the title outright.

And six different analyses have found that 2021 was between the fifth- and sixth-hottest on record, even though it was a La Niña year, which generally brings a cooling effect.

“The last eight years are the eight warmest years on record,” said Gavin Schmidt, director of the NASA Goddard Institute for Space Studies.

As the climate continues to warm, not every year will set a new record, he said, but “the temperature trends continue to rise and, in fact, accelerate, and so this really is just another continuation of the long-term trajectory of the climate.”

The average global temperature is about 2 degrees Fahrenheit warmer than it was in the late 1800s.

Though this may not have created a noticeable effect on day-to-day activities, this seemingly incremental shift comes with devastating repercussions across the planet.

Arctic sea ice is declining, sea levels are rising, wildfires and heat waves are getting worse and hurricanes are becoming more intense.

Related: Norway has one of the world's most ambitious climate change targets. But it's also a major oil producer and exporter.

Last year, a series of floods inundated cities in parts of China to Germany. Intense hurricanes and cyclones caused destruction, from Ida in the Atlantic Ocean to Tauktae in the Arabian Sea. And heat waves smothered communities from Canada’s British Columbia to parts of Russia. Argentina is currently experiencing a historic heat wave, which recently shut down the electrical grid in the capital Buenos Aires.

Part of a larger problem

A slight increase in global temperatures is just part of a larger problem.

“What we have is an energy imbalance. So, there is more energy coming into the system than is leaving.”

Gavin Schmidt, director of the NASA Goddard Institute for Space Studies

“What we have is an energy imbalance,” NASA’s Schmidt said. “So, there is more energy coming into the system than is leaving.”

Greenhouse gases emitted from burning fossil fuels end up trapping some of the sun’s energy on Earth each day, instead of letting it escape back into space.

And it’s a lotof trapped energy.

The amount of excess energy on Earth due to climate change was some 28 times more in 2021 than all the energy humans use each year, Schmidt said, for everything from driving our cars to flying our planes to heating and cooling every building on Earth.

“That’s a big number,” Schmidt said.

Related: Why COP26 is the ‘last, best hope’ for fighting climate change

Most of that extra energy is not going to warm up the Earth’s average surface temperature even though that’s the figure global climate change targets focus on.

“More than 90% — to be exact, 93% — of the additional heat due to global warming is going into the oceans,” saidRoxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology in the city of Pune.

“And that is equivalent to five to six Hiroshima atom bombs per second — per second — that much energy [is what] the oceans are absorbing.”

A separate study released this past week found that 2021 was, in fact, the hottest year on record for the world’s oceans. And all that extra energy is being linked to the extreme weather that we’re seeing around the world.

As an example, Koll points to Cyclone Tauktea, which made landfall in Gujarat, India, last May, with wind speeds of 100 miles per hour. It killed some 174 people.

The storm formed in the Arabian Sea, which used to be the cooler, quieter cousin to the Bay of Bengal, but rising ocean temperatures have changed that.

As ocean temperatures heat up, Koll explained, more water at the surface evaporates. This warm, moist air acts as fuel for hurricanes. When it rises and cools, it condenses into clouds that can be whipped up into storm systems.

Around the world, as more water evaporates from hotter oceans, the warmed-up air can then hold more of that moisture. That, in turn, sets the stage for another symptom of climate change: heavier downpours.

“The warmer the ocean, the more intense these kinds of convective activities [become].”

Roxy Mathew Koll, climate scientist at the Indian Institute of Tropical Meteorology in Pune

“The warmer the ocean, the more intense these kinds of convective activities [become],” Koll said. “The more supply of moisture, more supply of heat into the atmosphere, and there we get more intense cyclones or more intense cloud systems, which can provide a lot of intense rainfall.”

Xuebin Zhang, senior research scientist with Canada’s national environment agency, said, “With warming, the amount of moisture contained in the air has increased quite a bit.”

“It's roughly about [a] 7% increase per 1 degree [Celsius] warming.”

Related: COP26 made incremental progress but failed to deliver on ‘transformational’ change, negotiators say

Catastrophic results

The human cost of these storms can be catastrophic.

The heavy rains in China’s central Hunan province last July triggered floods that led to 24 deaths, destroyed roughly 21,300 homes and damaged more than 1.5 million acres of farmland, according to official state media.

Zhang said it’s likely that climate change was partly to blame for that flooding. Eight inches of rain fell in a single hour.

“As a result, streets were full of water because the drainage system was not designed to drain so much water,” Zhang said.

And even though a warmer surface temperature is just one small symptom of the climate problem, it can wreak quite a lot of havoc.

Europe and the continental US saw their hottest summers ever in 2021, according to US and EU science agencies.

Canada broke its own high temperature record three days in a row, and nearly 600 people died in British Columbia due to the “heat dome” that settled over the region in June and July.

Related: Who will pay for ‘losses and damages’ caused by climate change? Developing countries make their case at COP26.

David Phillips, senior climatologist at Canada’s national environment agency, said in June that the heat in British Columbia was “unprecedented.”

“Historically we’ve never seen this before,” he told PBS. “It's like a different world for us here.”

Scientists who analyzed this summer’s North American heat wave said it would have been nearly impossible without all the extra energy that was trapped on Earth due to climate change.

“The amount of climate change that we’ve had has made this event 150 times more likely than it would have been in the past,” said Faron Anslow, a climatologist with the Pacific Climate Impacts Consortium in British Columbia. “In the late 1800s, an event like this would have been a one-in-150,000 year event.”

Now it’s only a one-in-1,000-year event.

And sometime in the not-to-distant future, it could even happen once every five or 10 years.