As I write this, I have now been officially stuck in my house for 10 days. Here, in Oregon, we’ve been under an Arctic blast for more than a week, and the icy hills and roads where I live have kept us “highlanders” unable to leave our premises.
In stark contrast to my predicament, NASA recently confirmed that 2023 was the hottest year on record. Global temperatures last year were about 2.1 degrees Fahrenheit (1.2 degrees Celsius) above the average for NASA’s baseline period (1951–1980). And that record heat across the world profoundly impacted the global water cycle in 2023, contributing to severe bushfires, floods, megadroughts and storms, new research shows.
To make that all a bit more digestible, a new report titled 10 New Insights in Climate Science summarizes the latest and most pivotal climate science research from the previous 18 months, synthesized to help policymakers through 2024 and beyond.
Hottest year recorded
In 2023, hundreds of millions of people around the world experienced extreme heat, and each month from June through December set a global record for the respective month. July was the hottest month ever recorded. Overall, Earth was about 2.1 degrees Fahrenheit (or about 1.2 degrees Celsius) warmer in 2023 than the late 19th-century average, when modern recordkeeping began. In fact, a total of 77 countries experienced the highest average annual temperature in at least 45 years.
NASA assembled its temperature record using surface air temperature data collected from tens of thousands of meteorological stations, as well as sea surface temperature data acquired by ship- and buoy-based instruments. This data was analyzed using methods that account for the varied spacing of temperature stations around the globe and for urban heating effects that could skew the calculations. Independent analyses were provided by NOAA and the Met Office Hadley Center, one of the United Kingdom’s foremost climate change research centers.
Though scientists have conclusive evidence that the planet’s long-term warming trend is driven by human activity and our fossil-fuel emissions, they still examine other phenomena that can affect yearly or multiyear changes in climate, such as aerosols, El Ninos, pollution and volcanic eruptions.
Typically, the largest source of year-to-year variability is an El Nino—a climate pattern that describes the unusual warming of surface waters in the eastern equatorial Pacific Ocean. The pattern has a second phase called La Nina, when trade winds are stronger than usual, pushing more warm water toward Asia. Off the west coast of the Americas, upwelling increases, bringing cold, nutrient-rich water to the surface. From 2020 to 2022, the Pacific Ocean saw three consecutive La Nina events, which tend to cool global temperatures. In May 2023, the ocean transitioned from La Nina to El Nino, which often coincides with the hottest years on record.
However, the record temperatures in the second half of 2023 occurred before the peak of the current El Nino event. So, scientists expect to see the biggest impacts of El Nino in February, March and April of 2024.
Researchers have also investigated the possible impacts from the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai undersea volcano, which blasted water vapor and fine particles, or aerosols, into the stratosphere. A recent study found that by reflecting sunlight away from the Earth’s surface, the volcanic aerosols led to an overall slight cooling of less than 0.2 degrees Fahrenheit (or about 0.1 degrees Celsius) in the Southern Hemisphere following the eruption.
But even with occasional cooling factors such as volcanoes or aerosols, say the scientists, we will continue to break records as long as greenhouse gas emissions keep going up. And, unfortunately, we just set a new record for greenhouse gas emissions again this past year.
Worst storms experienced
This exceptional warming—something we’ve never seen before in human history—is also having impacts in rainfall and coastal flooding.
In a new report by the Global Water Monitor Consortium, a research team from the Australian National University used data from thousands of ground stations and satellites orbiting the Earth to provide real-time information on air humidity, air temperature, flooding, lake volumes, rainfall, river flows, soil and groundwater conditions, and vegetation. They found that the lack of rainfall and high temperatures exacerbated multiyear droughts in South America, the Horn of Africa and around the Mediterranean. Extremely hot and dry conditions inflicted extensive ecological damage on the world’s largest forests. Massive wildfires ravaged Canada during the northern summer, while the Amazon rain forest and rivers rapidly descended into severe drought in late 2023.
Rising sea-surface and air temperatures caused by fossil-fuel burning have been intensifying the strength and rainfall intensity of cyclones, monsoons and other storm systems. In Australia, for example, Cyclone Jasper battered northern Queensland and severe storms hit southeast Queensland. Some areas around Cairns recorded more than 31 inches of rain, causing widespread flooding.
The recent cyclones and intensive storms in Queensland and elsewhere in Australia should not be seen as isolated freak events, state the scientists, but part of a global pattern that was quite clear in 2023, where cyclones behaved in unexpected and deadly ways. The longest-lived cyclone ever recorded battered southeastern Africa for weeks.
Warmer sea temperatures fueled those abnormal behaviors, and we can expect to see more of these extreme events going forward. In the last two decades, increased air temperatures and declining air humidity have caused increased heat stress and water requirements for crops, ecosystems and people, while intensifying droughts.
Relative air humidity over the global land surface in 2023 was the second driest on record after 2021, continuing a trend towards drier and more extreme conditions. This is in line with ongoing changes in the water cycle over the last two decades. Globally, there’s an increase in the frequency and intensity of rainfall events and river flooding. But at the same time, there are more frequent and faster developing droughts, or “flash droughts.” That can cause crop failure and destructive wildfires in a matter of weeks or months.
With the current biodiversity crisis, a global food challenge and an extremely urgent need to reduce carbon emissions, the researchers say these droughts and wildfires are among our greatest threats.
A new report titled 10 New Insights in Climate Science, a collaborative initiative of the Earth League, Future Earth and the World Climate Research Program, synthesizes the latest developments in climate change research and aims to equip policymakers with the latest and most pivotal climate science research from the previous 18 months. This year’s report represents the collective efforts of 67 leading researchers from 24 countries.
In its findings, the report underscores the looming inevitability of overshooting the Paris Agreement’s 1.5 degrees Celsius global warming target, emphasizing the urgency of a rapid and managed fossil-fuel phaseout.
The 10 insights are:
1) Overshooting 1.5 degrees Celsius is fast becoming inevitable, greatly increasing risks as mitigation action is delayed.
2) A rapid and equitable fossil-fuel phaseout is required to stay within the Paris Agreement’s target range.
3) Robust policies are critical to attain the scale needed for effective carbon dioxide removal.
4) Overreliance on natural carbon sinks is a risky strategy; their future contribution is uncertain.
5) The climate and biodiversity emergencies and their solutions are intimately linked.
6) Compound events amplify climate risks and increase their uncertainty.
7) Mountain glacier loss is accelerating.
8) Human immobility in areas with climate risks is increasing.
9) New tools to operationalize justice enable more effective climate adaptation.
10) Reforming food systems can contribute to more just climate action.
Some of these insights offer important aspects that need to be considered as we confront this challenge head-on. The fifth insight emphasizes how the climate and biodiversity crises are fundamentally interconnected and must be addressed together. The ninth insight puts justice at the center of climate adaptation, which is critical in developing countries; while the 10th insight references the acute need for food-system transformations that can contribute to climate action.
In Africa, there is a lot of emphasis on carbon removal as an important mechanism for staying within the 1.5 degrees Centigrade Paris Agreement target (the third insight); but as the fourth insight shows, relying on natural carbon sinks is risky. “Natural” climate solutions, such as planting trees that sequester carbon, need to be done very carefully because of the potential for undermining ecosystems and livelihoods. For example, afforestation in grassy ecosystems (such as grasslands and savannas) might not sequester carbon effectively (as these systems store carbon in the soil rather than above ground), while impacting biodiversity and livelihoods such as pastoralism. Important caveats come from taking all the insights together.
While not a replacement for rapid and deep emissions reductions, carbon dioxide removal (CDR) will be a necessary, complementary technology to deal with hard-to-eliminate emissions and eventually to reduce the global temperature. Current CDR is predominantly forest-based, but rapid acceleration and deployment at scale of other CDR methods with permanent CO2 removal is required, supported by stronger governance and better monitoring.
The report spotlights the urgent need for enhanced, just climate adaptation strategies that address simultaneous, interconnected extreme events and that ensure resilience for the most vulnerable. It also accentuates the critical role of food systems in climate action, which are currently responsible for approximately one-third of global greenhouse gas emissions. It advocates for the rectification of existing inequalities and emphasizes that policies must be adapted to regional and sociocultural contexts, to enable the establishment of just, low-carbon food systems.
The intimate links between climate change mitigation and adaptation, biodiversity conservation and broader societal needs—including food security—require transformative changes in how we jointly govern socioecological systems. Most importantly, due to the growing risks of food insecurity, policies and solutions must be designed and implemented with those who suffer the most, conclude the report’s authors.
NASA and NOAA’s global temperature report confirms that billions of people around the world are facing a climate crisis. From extreme heat, to rising sea levels, to wildfires, we can see our Earth is changing.
But while the authors of the 10 New Insights in Climate Science report admit that there has been a lack of mitigation action to date, inadequate climate commitments by developed countries and a development model that remains coupled to carbon emissions, they believe that now is not the time to succumb to a feeling of hopelessness. Rather, this is the moment to find the new pathways that will get us started on a better trajectory for people and the planet.
There’s still more work to be done, but the current administration and communities across America are taking more action than ever to reduce climate risks and help all of us become more resilient. And NASA will continue to use the vantage point of space to bring critical climate data that is understandable and accessible back down to Earth.
I, too, won’t abandon hope that tomorrow the Arctic winds will die down, the ice will slide off the hillsides, and I will be able to step outside into the world again, ready to do what I can to help find solutions for the predicaments we all face.
Here’s to finding your true places and natural habitats,