On today's episode of the 5 Things podcast: Happy Earth Day!

The planet is in rough shape, but there's hope. Plus, personal finance and markets reporter Elisabeth Buchwald looks at Americans' increasing credit card use, new satellite images appear to show mass graves near Mariupol, graphics editor George Petras talks about ventilation systems on airplanes and a large wildfire keeps growing in Arizona.

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Hit play on the player above to hear the podcast and follow along with the transcript below. This transcript was automatically generated, and then edited for clarity in its current form. There may be some differences between the audio and the text.

Good morning. I'm Taylor Wilson and this is 5 Things you need to know, Friday the 22nd of April 2022. Today, Happy Earth Day, plus how Americans are swiping credit cards more frequently and more.

Here are some of the top headlines: 

Happy Earth Day. Rallies, protests, and other events are expected today and through the weekend as part of the annual observance of environmental issues. According to earthday.org, this year's theme is Invest In Our Planet. Earth Day 2022 comes just weeks after the United Nations' intergovernmental panel on climate change published a report warning that major action is needed immediately, to avoid unsustainable global warming. The panel's co-chair, Hans-Otto Pörtner, said waiting is not an option.

Based on the impacts we are seeing, based on the risks that are projected, every bit of warming matters. And the longer you wait, and the longer you follow the illusion that you have the option to make choices in with respect of not doing something, the more you will pay later.

The report found that current policy to try and curb global warming is not enough to limit warming to 1.5 degrees Celsius above pre-industrial levels. Scientists believe doing so is key to preventing catastrophe. The report found that total net greenhouse gas emissions continued to rise, during the years 2010 to 2019. The rate of growth was lower than between 2000 and 2009, but average annual emissions were higher than in any decade on record. A previous IPCC report also found that wealthier countries are disproportionately responsible for more emissions than developing ones, even though developing countries are experiencing more severe climate impacts. Some of the work being done to help us better understand our planet, and what needs to happen to fix it, comes from NASA. Karen St. Germain is the head of NASA's Earth Science Division.

NASA has been observing the Earth's system for decades using that unique vantage point of space to understand how our oceans and land and atmosphere, and even the polar regions, are working as a system and how they're changing over time. And over the last 50 years, our observations of our home planet have shown that our atmosphere is warming, our oceans are warming, and that's having a lot of impact on the global system. Ever since that famous Earthrise photo during the Apollo era, NASA has been taking that same technology, that same scientific expertise, and turning it back to understand our home planet.

The entire ecosystem of Earth observation has really accelerated just in the last five or six years. When we talk about how Earth's climate is changing, it might be easy to feel despair, but I really feel hopeful because I think the understanding we get from our satellite based systems, the way we see Earth as a system, gives us the information we need to make different decisions to actually manage what's ahead. So I think the science and technology can really help us manage in the future, and I think people should be hopeful about the future.

For more on some of the solutions to our climate crisis, check out our April 12th episode of 5 Things, with reporter Elizabeth Weise. As for Earth Day, it's not recognized as a federal holiday in the US, but Americans around the country have observed it for 52 years, as do more than a billion people worldwide. Today, President Joe Biden will spend the day in the Pacific Northwest, announcing new legislation to protect old growth forests from wildfires and climate change.

Without stimulus checks and a lapse in monthly child tax credit payments, Americans in dire financial situations are swiping credit cards more frequently than a year ago. Personal Finance and Markets reporter Elisabeth Buchwald explains.

We're starting to see that people who are having trouble paying bills are actually using their credit cards at higher rates than they did last year. And it's an important to keep in mind that, last year, inflation was about three times smaller than what it is right now. So people right now are turning to credit cards because they're most likely having trouble paying these bills, and it's easier to swipe a card as opposed to taking the cash out of your account if you don't have it. Now, the danger, of course, is not paying back that credit card bill on time means that you're probably going to be racking up credit card debt. And they're going to keep tacking on interest rates that are higher and higher, as the Federal Reserve raises interest rates.

So when the Federal Reserve raises interest rates, which they said they're going to do six more times this year, they already did it once earlier this year, and each time they do that, it becomes more expensive to take on debt in all forms. So be it a mortgage, be it a loan, but credit card debt is typically the most expensive one, the interest rates on that are the highest. And they've already started to go up a bit just from the one rate hike that we saw. And the more you sit on that, the more expensive it's going to be, just because of these rate hikes that the Fed is doing. And banks and credit card companies to be competitive, they have to match that essentially.

For more, head to USATODAY.com/money.

New satellite images appear to show mass graves near Mariupol, Ukraine. Local officials have accused Russia of burying up to 9,000 Ukrainian civilians to hide the slaughter taking place there in recent months. Images came out just hours after Russian President Vladimir Putin claimed victory yesterday in the battle for Mariupol, that's despite some 2,000 Ukrainian fighters still inside a steel mill complex there. But Putin ordered to blockade it instead of storming it. Britain's defense ministry said that move is likely to free up Russian forces for other fights in Eastern Ukraine. Russia has not commented on the satellite images of graves in Mariupol. Previously when mass graves and hundreds of dead civilians were found in suburbs around Kyiv, Russian officials denied that their soldiers killed civilians, and accused Ukraine of staging the atrocities.

In Mariupol, limited evacuations have continued by bus this week. Some 80 people made it to the city of Zaporizhzhia yesterday, out of some 1,500 who expected to leave, according to the Red Cross. And Russian officials reportedly even pulled some people off the buses. Evacuee Yuriy Lulac described the scene back home.

Taylor Wilson translating for Yuriy Lulac:

"Hell is what's happening there, it's not possible to just retell it. Russians are killing people for nothing. If the world doesn't take measures, Zaporizhzhia will be the same. Something needs to be done, as soon as possible."

At least two Russian attacks yesterday hit Zaporizhzhia, though no one was injured. Ukrainian authorities say more than 20,000 people have been killed in Mariupol, and about 100,000 people are estimated to remain with little food, water, heat, or other resources. Mariupol had a pre-war population of 430,000.

After a federal judge's ruling this week removing mask mandates on planes, the largest airlines in the country say they will not require them anymore. And they add that ventilation systems on board make transmission of COVID-19 difficult. Graphics editor George Petras has more.

Aircraft ventilation systems vary somewhat by manufacturer, but they're essentially engineered the same way. Now we drew from Boeing for our explainer. The aircraft's jet engines power its ventilation system. Now, in simple terms, outside air is circulated into the aircraft where it's cleaned by HEPA filters. That's an acronym for a high-efficiency particulate air filter. Now, the Environmental Protection Agency says these filters remove at least 99.8% of dust, mold, bacteria, and airborne particles. HEPA filters also catch the particles that contain coronaviruses. Now, after being filtered, the air is pumped to overhead ceiling ducts and then downward into the cabin, where other vents near the floor siphon it out. About half of the air is discharged from the aircraft, the other half is mixed with fresh air, filtered, and recirculated inside the plane.

Now, there is a catch. The aircraft's main engines must be operating to power the ventilation system. Now that means the plane must be in flight. If not in flight, commercial jets have an onboard auxiliary power unit that can be used to operate the system while the plane is on the ground. Now, fresh air can also be pumped in from an outside air compressor. Now, various medical studies say aircraft ventilation systems are highly efficient, but they still recommend that air travelers wear masks for extra protection. In comparing aircraft to buildings such as offices or stores, it really depends on the building itself. Newer buildings usually have more efficient air exchange and filtration systems. Now, building owners can upgrade their heating, ventilation and air conditioning systems to accommodate HEPA filters, and they can also do things like increase natural ventilation. But aircraft cabins have an advantage over office spaces because all the passengers are facing forward the same way. Passenger movement is restricted, no socializing, seat backs serve as air barriers, at least partially, the airflow is constant from the top of the cabin to the bottom, and the cabin air is filtered as we've described.

You can check out a visual explainer of plane ventilation systems with a link in today's show description.

A large wildfire near Flagstaff, Arizona is expected to keep growing today. About 30 structures have already been destroyed, and Santa Fe National Forest officials expect a potentially widespread and catastrophic fire weather event today. The 32 square mile blaze is one of a half dozen major wildfires in Arizona, New Mexico and Colorado over the past week. Forecasters warn that warm weather, little to no precipitation and spring winds create a dangerous recipe for wildfires.

Thanks for listening to 5 Things. You can find us right here, wherever you're listening right now, seven mornings a week. Thanks to PJ Elliott for his great work on the show, and I'm back tomorrow with more of 5 Things from USA TODAY.