The summer of 2022 started with a historic flood in Montana, brought on by heavy rain and melting snow, that tore up roads and caused large areas of Yellowstone National Park to be evacuated.

It ended with a record-breaking heat wave in California and much of the West that pushed the power grid to the breaking point, causing blackouts, followed by a tropical storm that set rainfall records in southern California. A typhoon flooded coastal Alaska, and a hurricane hit Puerto Rico with more than 30 inches of rain.

In between, wildfires raged through California, Arizona and New Mexico on the background of a megadrought in Southwestern U.S. that has been more severe than anything the region has experienced in at least 1,200 years. Near Albuquerque, New Mexico, a five-mile stretch of the Rio Grande ran dry for the first time in 40 years. Persistent heat waves lingered over many parts of the country, setting temperature records.

At the same time, during a period of five weeks between July and August, five 1,000-year rainfall events occurred in St. Louis, eastern Kentucky, southern Illinois, California’s Death Valley and in Dallas, causing devastating and sometimes deadly flash floods. Extreme rainfall also led to severe flooding in Mississippi, Virginia and West Virginia.

The United States is hardly alone in its share of climate disasters.

In Pakistan, record monsoon rains inundated more than one-third of the country, killing over 1,500 people. In India and China, prolonged heat waves and droughts dried up rivers, disrupted power grids and threatened food security for billions of people.

In Europe, heat waves set record temperatures in Britain and other places, leading to severe droughts and wildfires in many parts of the continent. In South Africa, torrential rains brought flooding and mudslides that killed more than 400 people. The summer may have come to an end on the calendar, but climate disasters will surely continue.

This isn’t just a freak summer: Over the years, such extreme events are occurring in increasing frequency and intensity.

Climate change is intensifying these disasters

The most recent international climate assessment from the United Nations’ Intergovernmental Panel on Climate Change found significant increases in both the frequency and intensity of extreme temperature and precipitation events, leading to more droughts and floods.

A recent study published in the scientific journal Nature found that extreme flooding and droughts are also getting deadlier and more expensive, despite an improving capacity to manage climate risks. This is because these extreme events, enhanced by climate change, often exceed the designed levels of such management strategies.

Extreme events, by definition, occur rarely. A 100-year flood has a 1% chance of happening in any given year. So, when such events occur with increasing frequency and intensity, they are a clear indication of a changing climate state.

The term “global warming” can sometimes be misleading, as it seems to suggest that as humans put more heat-trapping greenhouse gases into the atmosphere, the world is going to get a bit warmer everywhere. What it fails to convey is that warming temperatures also lead to a more violent world with more extreme climate disasters, as we saw this past summer.

Climate models showed these risks were coming

Much of this is well-understood and consistently reproduced by climate models.

As the climate warms, a shift in temperature distribution leads to more extremes. The magnitudes of changes in extreme temperature are often larger than changes in the mean. For example, globally, a 1 degree Celsius increase in annual average temperature is associated with 1.2 C to 1.9 C (2.1 Fahrenheit to 3.4 F) of increase in the annual maximum temperature.

In addition, global warming causes changes in the vertical profile of the atmosphere and equator-to-pole temperature gradients, leading to changes in how the atmosphere and ocean move. The temperature difference between equator and the poles is the driving force for global wind. As the polar regions warm at much higher rates then the equator, the reduced temperature difference causes a weakening of global winds and leads to a more meandering jet stream.

Some of these changes can create conditions such as persistent high-pressure systems and atmosphere blocking that favor more frequent and more intense heat waves. The heat domes over the Southern Plains and South in June and the West in September are examples.

The initial warming can be further amplified by positive feedbacks. For example, warming increases snow melt, exposing dark soil underneath, which absorbs more heat than snow, further enhancing the warming.

Warming of the atmosphere also increases its capacity to hold water vapor, which is a strong greenhouse gas. Therefore, more water vapor in the air leads to more warming. Higher temperatures tend to dry out the soil, and less soil moisture reduces the land’s heat capacity, making it easier to heat up.

These positive feedbacks further intensify the initial warming, leading to more heat extremes. More frequent and persistent heat waves lead to excessive evaporation, combined with decreased precipitation in some regions, causing more severe droughts and more frequent wildfires.

Higher temperatures increase the atmosphere’s capacity to hold moisture at a rate of about 7% per degree Celsius.

This increased humidity leads to heavier rainfall events. In addition, storm systems are fueled by latent heat, or the large amount of energy released when water vapor condenses to liquid water. Increased moisture content in the atmosphere also enhances latent heat in storm systems, increasing their intensity. Extreme heavy or persistent rainfall leads to increased flooding and landslides, with devastating social and economic consequences.

Even though it’s difficult to link specific extreme events directly to climate change, when these supposedly rare events occur with increasing frequency in a warming world, it is hard to ignore the changing state of our climate.

The new abnormal

So this past summer might just provide a glimpse of our near future, as these extreme climate events become more frequent.

To say this is the new “normal,” though, is misleading. It suggests that we have reached a new stable state, and that is far from the truth.

Without serious effort to curb greenhouse gas emissions, this trend toward more extreme events will continue. Things will keep getting worse, and this past summer will become the norm a few years or decades down the road – and eventually, it will seem mild, like one of those “nice summers” we look back on fondly with nostalgia.

Shuang-Ye Wu, Professor of Geology and Environmental Geosciences, University of Dayton

This article is republished from The Conversation under a Creative Commons license. Read the original article.

On Sept. 26, 2022, NASA plans to change an asteroid’s orbit.

The large binary asteroid Didymos and its moonlet Dimorphos currently pose no threat to Earth. But by crashing a 1,340-pound (610-kilogram) probe into Didymos’ moon at a speed of approximately 14,000 mph (22,500 kph), NASA is going to complete the world’s first full-scale planetary defense mission as a proof of concept. This mission is called the Double Asteroid Redirection Test, or DART.

I am a scholar who studies space and international security, and it is my job to ask what the likelihood really is of an object crashing into the planet – and whether governments are spending enough money to prevent such an event.

To find the answers to these questions, one has to know what near-Earth objects are out there. To date, NASA has tracked only an estimated 40% of the bigger ones. Surprise asteroids have visited Earth in the past and will undoubtedly do so in the future. Experiments like the DART mission may help prepare humanity for such an event.

The threat from asteroids and comets

Millions of cosmic bodies, like asteroids and comets, orbit the Sun and often crash into the Earth. Most of these are too small to pose a threat, but some can be cause for concern. Near-Earth objects include asteroids and comets whose orbits will bring them within 120 million miles (193 million kilometers) of the Sun.

Astronomers consider a near-Earth object a threat if it will come within 4.6 million miles (7.4 million kilometers) of the planet and if it is at least 460 feet (140 meters) in diameter. If a celestial body of this size crashed into Earth, it could destroy an entire city and cause extreme regional devastation. Larger objects – 0.6 miles (1 kilometer) or more – could have global effects and even cause mass extinctions.

The most famous and destructive celestial impact took place 65 million years ago when an asteroid with a 6-mile (10-kilometer) diameter crashed into what is now the Yucatán Peninsula. It wiped out most plant and animal species on Earth, including the dinosaurs.

But smaller objects can also cause significant damage. In 1908, an approximately 164-foot (50-meter) celestial body exploded over the Podkamennaya Tunguska River in Siberia. It leveled more than 80 million trees over 830 square miles (2,100 square kilometers). In 2013, an asteroid only 65 feet (20 meters) across burst in the atmosphere 20 miles (32 kilometers) above Chelyabinsk, Russia. It released the equivalent of 30 Hiroshima bombs’ worth of energy, injured over 1,100 people and caused US$33 million in damage.

The likely next asteroid of substantial size to potentially hit Earth is asteroid 2005 ED224. When the 164-foot (50-meter) asteroid passes by on March 11, 2023, there is roughly a 1 in 500,000 chance of impact.

Watching the skies

While the chances of a larger cosmic body striking Earth are small, the devastation would be enormous.

Congress recognized this threat, and in the 1998 Spaceguard Survey, it tasked NASA to find and track 90% of the estimated total of near-Earth objects 0.6 miles (1 kilometer) across or bigger within 10 years. NASA surpassed the 90% goal in 2011.

In 2005, Congress passed another bill requiring NASA to expand its search and track at least 90% of all near-Earth objects 460 feet (140 meters) or larger by the end of 2020. That year has come and gone and, mostly because of a lack of financial resources, only 40% of those objects have been mapped.

As of Sept. 18, 2022, astronomers have located 29,724 near-Earth asteroids, of which 10,189 are 460 feet (140 meters) or larger in diameter and 855 are at least 0.6 miles (1 kilometer) across. About 30 new objects are added each week.

A new mission funded by Congress in 2018 is scheduled in 2026 to launch an infrared space-based telescope – NEO Surveyor – dedicated to searching for potentially dangerous asteroids.

Cosmic surprises

We can prevent a disaster only if we know it is coming, and asteroids have sneaked up on Earth before.

A so-called “city-killer” asteroid the size of a football field passed less than 45,000 miles (72,420 kilometers) from Earth in 2019. An asteroid the size of a 747 jet came close in 2021, as did an asteroid 0.6 miles (1 kilometer) wide in 2012. Each of these was discovered only about a day before it passed Earth.

Research suggests that Earth’s rotation creates a blind spot, hiding some asteroids from detection or making them appear stationary. This may be a problem, as some surprise asteroids do not miss us. In 2008, astronomers spotted a small asteroid only 19 hours before it crashed into rural Sudan.

The recent discovery of an asteroid 1.2 miles (2 kilometers) in diameter suggests that there are still big objects lurking.

What can be done?

To protect the planet from cosmic dangers, early detection is key. At the 2021 Planetary Defense Conference, scientists recommended a minimum of five to 10 years’ preparation time to mount a successful defense against hazardous asteroids.

If astronomers find a dangerous object, there are four ways to mitigate a disaster. The first involves regional first-aid and evacuation measures. A second approach would involve sending a spacecraft to fly near a small- or medium-sized asteroid; the gravity of the craft would slowly change the object’s orbit. To change a bigger asteroid’s path, we can either crash something into it at high speed or detonate a nuclear warhead nearby.

The DART mission will be the first-ever attempt to deflect a large asteroid. But this will not be the first time humanity has sent something to an asteroid. NASA’s Deep Space Impact mission crashed a probe into the comet 9P/Tempel in 2005 to take scientific measurements of the comet, and in 2018 Japan’s Hayabusa2 mission collected samples from the asteroid Ryugu and brought them back to Earth, but neither of these was designed as a planetary defense test.

The DART mission should generate a lot of useful information. This data will come from a camera aboard the DART spacecraft that will send images back to Earth up until the time of impact. In addition, a tiny satellite called LICIACube that was deployed from DART on Sept. 11, 2022, will take photos of the impact. A follow-up mission from the European Space Agency, called Hera, will launch in 2024 and rendezvous with Didymos in 2026 to begin collecting data.

Spending on planetary defense

In 2021, NASA’s planetary defense budget was $158 million, just 0.7% of NASA’s total budget and 0.02% of the roughly $700 billion U.S. defense budget.

Is this the right amount to invest in monitoring the skies, given the fact that some 60% of all potentially dangerous asteroids remain undetected? This is an important question to ask when one considers the potential consequences.

Investing in planetary defense is akin to buying homeowners insurance. The likelihood of experiencing an event that destroys your house is small, yet people buy insurance nonetheless.

If even a single object larger than 460 feet (140 meters) hits the planet, the devastation and loss of life would be extreme. A bigger impact could quite literally wipe out most species on Earth. Even if no such body is expected to hit Earth in the next 100 years, the chance is not zero. In this low-likelihood-versus-high-consequences scenario, investing in protecting the planet from dangerous cosmic objects may give humanity some peace of mind and could prevent a catastrophe.

This is an updated version of a story originally published on March 1, 2022.

Svetla Ben-Itzhak, Assistant Professor of Space and International Relations, Air University

This article is republished from The Conversation under a Creative Commons license. Read the original article.