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The summer 2021 heatwave in the Pacific Northwest stood out even in a world that is increasingly affected by extreme weather events. For several days in June, cities like Vancouver and Portland were sweltering hot. Baked at record temperaturesThis caused the deaths of hundreds. On June 29, Lytton, a village in British Columbia, set an all-time heat record for Canada, at 121° Fahrenheit (49.6° Celsius); the next day, the village was incinerated by a wildfire.
In less than a week, a group of international scientists had examined the extreme heat and concluded that it would not have been possible without climate change. The planet’s average surface temperature has risen by at least 1.1 degrees Celsius since preindustrial levels of 1850–1900. The reason is that people are adding heat-trapping gases to the atmosphere from the burning of fossil fuels like coal and gas and from reducing forests.
Although it may not seem like much, a little more than 1 degree of warming is significant. But it has already had an impact on fundamentally changing how energy flows around our planet. The pace of change is increasing, and the consequences are everywhere. The ice sheets are in GreenlandAnd Antarctica melting, causing sea levels to rise and flooding low-lying islands and coastal cities. Drought is threatening the waterways and farmlands. Wildfires are raging. Rains are getting more intense and Weather patterns are changing.
Understanding the climate emergency is rooted in more than a century and half back. But it wasn’t until the 1950s that scientists began the detailed measurements of atmospheric carbon dioxide that would prove how much carbon is pouring from human activities. Researchers began to develop computer models that accurately reflect the severity of the changes in the 1960s.
Today, we know climate change and its effects are real. We are responsible. The emissions that people have been putting into the air for centuries — the emissions that made long-distance travel, economic growth and our material lives possible — We are now on a warming path. Only drastic reductions of carbon emissions can make a big difference, if backed up by global collective will.
“What’s happening to the planet is not routine,” says Ralph Keeling, a geochemist at the Scripps Institution of Oceanography in La Jolla, Calif. “We’re in a planetary crisis.”
Cole Burston/AFP via Getty Images
Setting the stage
One day in the 1850s, Eunice Newton Foote, an amateur scientist and a women’s rights activist living in upstate New York, put two glass jars in sunlight. One contained regular air — a mix of nitrogen, oxygen and other gases including carbon dioxide — while the other contained just carbon dioxide. Both contained thermometers. As the sun’s rays beat down, Foote observed that the jar of CO2The one containing pure air warmed up faster and took longer to cool down than the one without it.
Foote was inspired to reflect upon the relationship between CO and these results.2heat, the planet. “An atmosphere of that gas would give to our earth a high temperature,” she wrote in an 1856 paper summarizing the findings.
Three years later, working independently and apparently unaware of Foote’s discovery, Irish physicist John Tyndall showed the same basic idea in more detail. He was able to determine the transmission of heat using a set of pipes.2Gas and water vapor absorb more heat that air alone. He argued that such gases would trap heat in Earth’s atmosphere, much as panes of glass trap heat in a greenhouse, and thus modulate climate.
Tyndall is widely acknowledged today as having discovered how greenhouse gases heat the planet. This earned him a prominent position in the history climate science. Foote faded into relative obscurity — partly because of her gender, partly because her measurements were less sensitive. Yet their findings helped kick off broader scientific exploration of how the composition of gases in Earth’s atmosphere affects global temperatures.
Carbon flooding in
Around the turn of 19th century, the Industrial Revolution in Britain saw the beginning of significant human influence on the atmosphere. Factories used tons of coal to power their steam engines, which were fueled by fossil fuels. This engine revolutionized transportation as well as other industries. To drive a global economy, fossil fuels such as oil and natural gas have been harnessed since then. All of these activities release gases into the atmosphere.
Yet Swedish physical chemist Svante Arrhenius wasn’t worried about the Industrial Revolution when he began thinking in the late 1800s about changes in atmospheric CO2 levels. He was instead curious about ice ages — including whether a decrease in volcanic eruptions, which can put carbon dioxide into the atmosphere, would lead to a future ice age. After a divorce, Arrhenius was bored and lonely and began months of tedious calculations involving heat transport and moisture in the atmosphere at different latitudes. In 1896, he reported on halving the CO content.2The atmosphere could lead to an ice age — and that doubling CO2Global temperatures would rise by approximately 5-6 degrees Celsius
It was a remarkably prescient finding for work that, out of necessity, had simplified Earth’s complex climate system down to just a few variables. But Arrhenius’ findings didn’t gain much traction with other scientists at the time. The climate system was too complex, inert, and large to be changed in any meaningful manner on a timescale that would make it relevant to human society. For example, geologic evidence demonstrated that ice ages took thousands upon thousands of years to form and disappear. What was to be worried about?
One researcher though thought the idea was worth considering. Guy Stewart Callendar, an amateur meteorologist and engineer from Britain, had tracked weather records over time and determined that average temperatures were rising at 147 weather stations around Earth. He published his 1938 paper in the Royal Meteorological Society journal. This temperature rise has been linked to the burning of fossilfuels. Callendar estimated that fossil fuel combustion had produced around 150 billion metric tonnes of CO.2In the atmosphere since the late 19th Century.
Like many of his day, Callendar didn’t see global warming as a problem. Extra CO2This would stimulate plant growth and allow for new cropping. “In any case the return of the deadly glaciers should be delayed indefinitely,” he wrote. His work revived discussions that harked back to Tyndall, Arrhenius and discussed how the planet system reacts to changes in the atmospheric gases. It also led to a discussion about how human activities might cause these changes.
The global conflict reshaped the landscape for scientific research when World War II broke out in the year that followed. Hugely important wartime technologies, such as radar and the atomic bomb, set the stage for “big science” studies that brought nations together to tackle high-stakes questions of global reach. This allowed for modern climate science.
The Keeling curve
One major effort was the International Geophysical Year, or IGY, an 18-month push in 1957–1958 that involved a A wide range of scientific field campaignsThis includes exploration in the Arctic, Antarctica. Climate change wasn’t a high research priority during the IGY, but some scientists in California, led by Roger Revelle of the Scripps Institution of Oceanography, used the funding influx to begin a project they’d long wanted to do. The goal was to measure CO.2Different locations around the globe, accurately and consistently.
Charles David Keeling, a geochemist, was appointed to the job. He used ultraprecise carbon dioxide.2Monitors in Antarctica as well as on Mauna Loa volcano in Hawaii. The Antarctic record was quickly lost, but Mauna Loa measurements were not stopped. Thus was born one of the most iconic datasets in all of science — the “Keeling curve,” which tracks the rise of atmospheric CO2.
CO was the place where Keeling started his measurements in 1958.2315 parts per billion of the world’s atmosphere. In just a few short years, it was clear that the number was increasing each year. Because plants take up CO2CO is released as they grow in spring/summer and then release it as their decomposition in fall/winter.2The sawtooth pattern shows that concentrations change each year. Surrounding that pattern was a steady march up.
“The graph got flashed all over the place — it was just such a striking image,” says Ralph Keeling, who is Keeling’s son. Over the years, as the curve marched higher, “it had a really important role historically in waking people up to the problem of climate change.” The Keeling curve has been featured in countless earth science textbooks, congressional hearings and in Al Gore’s 2006 documentary on climate change, An Inconvenient Truth.
Each year, the curve keeps increasing: In 2016, it surpassed 400 ppm CO2The atmosphere as measured at its annual minimum in September. It is currently at 413ppm. (CO was the precursor to the Industrial Revolution.2Levels in the atmosphere were stable for centuries at around 220 ppm.
Around the time that Keeling’s measurements were kicking off, Revelle also helped develop an important argument that the CO2 from human activities was building up in Earth’s atmosphere. He and Hans Suess, who were also at Scripps at that time, published a paper in 1957. The flow of radioactive Carbon through the oceans, and the atmosphere was traced. They found that the oceans could not absorb as much CO.2As previously thought, this implied that a lot of the gas must be entering the atmosphere.
“Human beings are now carrying out a large-scale geophysical experiment of a kind that could not have happened in the past nor be reproduced in the future,” Revelle and Suess wrote in the paper. It’s one of the most famous sentences in earth science history.
The insight behind modern climate science was this: Atmospheric CO2 is increasing and humans are contributing to it. Revelle and Suess were the final pieces in a puzzle that dates back to John Tyndall and Svante Arhenius. “I tell my students that to understand the basics of climate change, you need to have the cutting-edge science of the 1860s, the cutting-edge math of the 1890s and the cutting-edge chemistry of the 1950s,” says Joshua Howe, an environmental historian at Reed College in Portland, Ore.
Evidence piles up
Researchers slowly began to understand the effects of human activity on the planet by using observational data from the second half of 20th century.
Ice cores from ice sheets like that above Greenland offer some of the most valuable insights for understanding past climate changes. Each year, snow falls on top of the ice and is compressed into a new layer of ice. This represents the climate conditions at the time it formed. Scientists can calculate the temperature at which the ice formed by looking at the abundance of certain forms of oxygen or hydrogen in the ice. Additionally, air bubbles in the ice allow scientists to determine how much carbon dioxide and other greenhouse gasses were present at the time. It’s like looking through a history book, where you can go back in time by drilling down into the ice sheet.
These pages were first used by scientists in 1960. Use ice cores drilled at an American military base in northwest Greenland. Contrary to past climates being stable, the cores indicated that there had been abrupt climate shifts over the last 100,000 year. By 1979, an international group of researchers was pulling another deep ice core from a second location in Greenland — and it, too, showed that abrupt climate change had occurred in the past. In the late 1980s and early 90s, A pair of European-led and U.S.-led drilling programsDeeper cores were retrieved from the top ice sheet. This pushes the record of past temperatures back by 25% of a million year.
The ice cores, along with other information sources such as sediment cores from the seafloor or molecules preserved in old rocks, allowed scientists to reconstruct temperature changes in the past in incredible detail. Many of these changes happened at an alarming rate. Greenland’s climate is one example. Over 20 times, the earth has been warmed abruptly in the past 80,000 yearsThe changes are happening in a matter a few decades. More recently, a cold spell that set in around 13,000 years ago suddenly came to an end around 11,500 years ago — and In a decade, the temperatures in Greenland climbed 10 degrees Celsius.
The evidence for such dramatic climate shifts has dispelled any doubts that global climate change will be slow or not occur within a reasonable timeframe. “It’s an important reminder of how ‘tippy’ things can be,” says Jessica Tierney, a paleoclimatologist at the University of Arizona in Tucson.
Earth-observing satellites brought more evidence of global change, providing a new perspective from all around the globe on global warming that began in the 1960s. From their viewpoint in the sky, satellites have measured the rise in global sea level — currently 3.4 millimeters per year and accelerating, as warming water expands and as ice sheets melt — as well as the rapid decline in ice left floating on the Arctic Ocean each summer at the end of the melt season. Gravity-sensing satellites have “weighed” the Antarctic and Greenlandic ice sheets from above since 2002, reporting that more than 400 billion metric tons of ice are lost each year.
Temperature measurements taken at weather stations around world confirm that this is one of the hottest years ever recorded. The Since 2005, the 10 warmest years since records began in 1880 have all been recorded. And nine of those ten have arrived since 2010.
Worrisome predictions
In the 1960s, it was clear that the planet was heating up. But understanding the consequences of those changes — including the threat to human health and well-being — would require more than observational data. Computer simulations are used to predict the future. These complex calculations show how energy flows through the planet system.
The first step in building such climate models involved connecting weather observations to the idea of forecasting future climate. Lewis Fry Richardson, a British mathematician, imagined tens to thousands of meteorologists working together to forecast the future climate. Each one would calculate conditions for a specific part of the atmosphere, but they would all be able to create a global forecast.
But it wasn’t until after World War II that computational power turned Richardson’s dream into reality. Leading U.S. mathematicians were granted funding by the federal government to improve their predictions in the wake of the Allied victory. Jule Charney, a Princeton meteorologist, was part of a team that used the ENIAC to produce a 1950 report. This was the first U.S.-programmable electronic computer. The first computer-driven regional weather forecast. The forecasting was slow and rudimentary, but it built on Richardson’s ideas of dividing the atmosphere into squares, or cells, and computing the weather for each of those. This work was the foundation for climate modeling that would continue for decades.
By 1956, Norman Phillips, a member of Charney’s team, had produced the world’s first general circulation model, which captured how energy flows between the oceans, atmosphere and land. Climate modeling was created.
The work was basic at first because early computers simply didn’t have much computational power to simulate all aspects of the planetary system.
An important breakthrough came in 1967, when meteorologists Syukuro Manabe and Richard Wetherald — both at the Geophysical Fluid Dynamics Laboratory in Princeton, a lab born from Charney’s group — published a paper in the Journal of the Atmospheric Sciences that modeled connections between Earth’s surface and atmosphere and calculated how changes in CO2 would affect the planet’s temperature. Manabe, Wetherald and others were the first to notice. Build a computer model to capture the relevant processes driving climate changeTo accurately simulate how Earth responds to such processes.
Climate modeling enabled scientists to see the potential consequences of global warming more accurately. Charney and other experts met in Woods Hole (Mass.) in 1979 to attempt to reach a scientific consensus about the effects of increasing levels CO.2a positive impact on the planet. The resulting “Charney report” concluded that rising CO2Climate change could be exacerbated by changes in the atmosphere.
In the decades since, Climate modeling has become increasingly sophisticated. As climate science became more solid, climate change became a political topic.
Backlash
The rising public awareness of climate change, and battles over what to do about it, emerged alongside awareness of other environmental issues in the 1960s and ’70s. Rachel Carson’s 1962 book Silent SpringThe infamous ‘Death to DDT’ campaign, which condemned pesticide DDT for its ecological effects, catalyzed environmental activism and led to the creation of the first Earth Day in the United States in 1970.
In 1974, scientists discovered another major global environmental threat — the Antarctic ozone hole, which had some important parallels to and differences from the climate change story. Mario Molina and F. Sherwood Rowland (University of California, Irvine) reported that chlorofluorocarbon chemicals used in products such spray cans or refrigerants could cause a chain of reactions. gnawed away at the atmosphere’s protective ozone layer. The resulting ozone hole, which forms over Antarctica every spring, allows more ultraviolet radiation from the sun to make it through Earth’s atmosphere and reach the surface, where it can cause skin cancer and eye damage.
To create the 1987 Montreal Protocol, governments worked under the auspices United Nations. This strictly restricted the production of chlorofluorocarbons. The ozone hole began healing in the years that followed. But combating climate change has proven to be more difficult. It’s much harder to transform entire energy industries to reduce or eliminate carbon emissions than replacing a few industrial chemicals.
Researchers made an important step in 1980 to bring together scientists to synthesize climate change science and bring it to the attention international policy makers. It all began at a small scientific conference held in Villach (Austria) on the seriousness climate change. Bert Bolin, a Swedish meteorologist, spoke with other participants on the train home from the meeting about the need for a deeper, more comprehensive, and more international analysis. 1988 saw the birth of the United Nations’ Intergovernmental Panel on Climate Change. Bolin was its first chairman.
The IPCC was a unique and influential body. It performs no original scientific research; instead, it synthesizes and summarizes the vast literature of climate science for policy makers to consider — primarily through massive reports issued every couple of years. The 1990 IPCC Report was the first., predicted that the planet’s global mean temperature would rise more quickly in the following century than at any point in the last 10,000 years, due to increasing greenhouse gases in the atmosphere.
The IPCC reports have been a key part of providing scientific information to nations that are discussing how to stabilize greenhouse gases concentrations. This began with the Rio Earth Summit 1992The U.N. Framework Convention on Climate Change. The first international commitments to lower emissions were made at the annual U.N. climate change meetings. The Kyoto Protocol of 1977. It requires developed countries to reduce CO2 emissions.2Other greenhouse gases. The IPCC declared that the IPCC had the reality of climate warming is “unequivocal.”Al Gore was also awarded the Nobel Peace Prize in that same year for his work on climate change.
The IPCC process made sure that policy makers had the best science available when they came to the table for cutting emissions. Of course, nations did not have to abide by that science — and they often didn’t. In the 2000s, and 2010s, international meetings on climate discussed less science and more issues related to equity. China and India, for example, pointed out that their economies depend on energy and that the nations responsible for most of the historical greenhouse gas emissions, such as the United States and Canada, must lead the way in reducing them.
Residents of low-lying islands, which are at risk from sea level rise, gained visibility and influence at international negotiating forums. “The issues around equity have always been very uniquely challenging in this collective action problem,” says Rachel Cleetus, a climate policy expert with the Union of Concerned Scientists in Cambridge, Mass.
By 2015, the world’s nations had made some progress on the emissions cuts laid out in the Kyoto Protocol, but it was still not enough to achieve substantial global reductions. In 2015, the U.N. climate conference in Paris produced an agreement that would attempt to reduce global emissions. Limit global warming to 2 degrees Celsius, and preferably 1.5 degrees Celsius, above preindustrial levels.
Each country approaches the challenge of climate change in a different way. The United States, which receives approximately 80 percent of its energy through fossil fuels, has suffered major delays in climate action due to sophisticated attempts to downplay and criticize the science. ExxonMobil and other U.S. fossil-fuel companies worked for decades to convince politicians to take as few steps as possible to reduce emissions.
Such tactics undoubtedly succeeded in feeding politicians’ delay on climate action in the United States, most of it from Republicans. President George W. Bush In 2001, the country was expelled from the Kyoto ProtocolDonald Trump in a similar manner 2017 rejection of the Paris agreement. As late as 2015, the chair of the Senate’s environment committee, James Inhofe of Oklahoma, brought a snowball into Congress on a cold winter’s day to argue that human-caused global warming is a “hoax.”
Australia has a similar mix between right-wing denialism, fossil fuel interests, which has kept climate change commitments in flux. Prime ministers are elected over fierce debates about how Australia should respond to climate change.
Other nations have made progress. Some European countries such as Germany aggressively pursued renewable energies, including wind and solar, while activists such as Swedish teenager Greta Thunberg — The youth-action movement’s vanguard — pressured their governments for more.
The discussion about climate action has been dominated by India and China in recent years. China, which is now the world’s largest carbon emitter, declared several moderate steps in 2021 to reduce emissions, including that it would stop building coal-burning power plants overseas. India declared that it would strive to have net-zero carbon emissions by 2070. This was the first time India has announced this goal.
However, such promises continue to be criticized. The U.N. 2021 Conference. Climate Change Conference in Glasgow, Scotland, India was globally criticized for not committing to a complete phaseout of coal — although the two top emitters, China and the United States, have not themselves committed to phasing out coal. “There is no equity in this,” says Aayushi Awasthy, an energy economist at the University of East Anglia in England.
Face the future
Many times, scientists are seeing changes faster than they could have imagined a few decades ago. As they absorb more CO, the oceans are becoming more acidic.2This is a serious threat to tiny marine organisms that create protective calcium carbonate shells. These shells are essential for the marine food web. Coral reefs are being bleached as a result of warmer waters. Higher temperatures are driving animal species and plant species into areas where they don’t normally live, increasing the risk for extinction.
No one place on the planet is immune to these effects. Higher temperatures have caused major droughts in many areas. These droughts dry out the vegetation and provide fuel for new growth. Wildfires such like those that have decimated Australia’s cities have been the cause of many a wildfire.Recent years have seen a rise in interest in the Mediterranean and western North America.
Then there’s the Arctic, where temperatures are rising at more than twice the global average and communities are at the forefront of change. Permafrost thaws, causing structural damage to buildings, pipelines, and roads. Reindeer and caribou herders are concerned about the increased risk of parasites to their animals’ health. With less sea ice to protect the coast from storm erosion, The Inupiat village Shishmaref in Alaska is at risk from falling into the ocean.. It will have to move from the sand-barrier island onto the mainland.
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Climate change is affecting human life in a way that is becoming more pervasive and is causing extreme weather events to become more common. Displaced families gathered at a camp in Baidoa, Somalia to get water in 2017. This camp is located near the city of Baidoa where hundreds of thousands of people fled drought. Tony Karumba/AFP via Getty Images -
In Europe, heavy rains and flash floods caused debris to strewn across streets in cities like Euskirchen, Germany, in July 2021 (shown). Gabriel Bouys/AFP via Getty Images -
This home was destroyed by beach erosion in Shishmaref in Alaska in 2006. The entire village now has to move due to sea level rise. Abdulhamid Hosbas/Anadolu Agency via Getty Images
“We know these changes are happening and that the Titanic is sinking,” says Louise Farquharson, a geomorphologist at the University of Alaska Fairbanks who monitors permafrost and coastal change around Alaska. Climate change is most dangerous to those who depend on intact ecosystems for survival. Those with the smallest resources to adapt to climate changes are the ones most affected.
“We are going to warm,” says Claudia Tebaldi, a climate scientist at Lawrence Berkeley National Laboratory in California. “There is no question about it. The only thing that we can hope to do is to warm a little more slowly.”
That’s one reason why The IPCC report of 2021 focuses primarily on global warming levels.. There is a significant difference in the planet’s warming of 1.5 degrees versus 2 or 2.5 degrees. Each degree of global warming increases the chance of extreme events like heat waves or heavy rains, which can lead to greater global destruction.
The future depends on how many nations are willing to cut emissions and whether they stick to their commitments. It’s a geopolitical balancing act the likes of which the world has never seen.
Science can and must play an important role in moving forward. Improved climate models can help officials anticipate and prepare for changes at the regional scale. Both industry and governments have important roles to play. They can invest in technologies such as carbon sequestration to help decarbonize society and shift society towards more renewable energy sources.
Huge questions remain. Are voters ready to demand energy transitions from their government? How can business and military leaders play an even bigger role in climate action efforts? What should be the role for low-carbon energy sources with potential downsides such as nuclear power? How can developing nations improve their standard-of-living while not becoming major greenhouse gas emitters? How can we ensure that the most vulnerable are not disproportionately affected by extreme events and how can we incorporate environmental and social justice in our future?
These questions are becoming more urgent each year as carbon dioxide accumulates in the atmosphere. The planet is now experiencing higher levels of CO2 than at any time in the last 3 million years.
Diplomats from all over the world agreed to urgently shift from fossil fuels at the U.N. Climate Meeting in Glasgow in 2021. However, they did not set targets that would keep the world from warming by 1.5 degrees.
It’s been well over a century since chemist Svante Arrhenius recognized the consequences of putting extra carbon dioxide into the atmosphere. The world has not come together to prevent the most serious consequences of climate change.
The clock is ticking.
