James Hansen facts for kids
Quick facts for kids
James Hansen
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Hansen in 2005
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James Edward Hansen
March 29, 1941 Denison, Iowa, U.S.
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| Alma mater | University of Iowa |
| Known for |
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| Awards |
BBVA Foundation Frontiers of Knowledge Award (2016) Tang Prize (2018) Heinz Award in the Environment (2001) |
| Scientific career | |
| Fields | Atmospheric physics |
| Institutions | Currently Columbia University; NASA Goddard Institute for Space Studies 1967–2013 |
| Thesis | The atmosphere of Venus : a dust insulation model (1967) |
| Doctoral advisor | Satoshi Matsushima |
James Edward Hansen (born March 29, 1941) is an American scientist. He is a professor at Columbia University and used to lead a special climate science program there. He is famous for his work on climatology, which is the study of Earth's climate.
In 1988, he gave an important speech to the U.S. Congress. This speech helped many people understand global warming and climate change. Hansen also believes we need to act now to stop dangerous climate change. Because of his strong beliefs, he has sometimes joined protests to help protect the environment.
Hansen also suggested that the Earth's temperature has risen by about 0.7°C in the last 100 years. He thinks this warming is mostly due to greenhouse gases other than carbon dioxide, like methane.
Contents
Early Life and Education
James Hansen was born in Denison, Iowa, in the United States. He studied physics and astronomy at the University of Iowa. He earned his bachelor's degree in physics and mathematics in 1963. He then got his master's degree in astronomy in 1965. Finally, he received his Ph.D. in physics in 1967.
While studying, he also spent time as a visiting student in Japan. In 1967, he started working at the Goddard Institute for Space Studies. This is a part of NASA.
Career in Climate Science
After finishing his studies, Hansen continued to work on models that help us understand how light and heat move through the air. He first used these models to study the atmosphere of Venus. Later, he used them to understand Earth's atmosphere. He focused on how tiny particles (called aerosols) and certain gases affect our planet's climate.
Hansen also helped develop and use global climate models. These are like giant computer programs that help scientists understand Earth's climate. From 1981 to 2013, he was the director of the NASA Goddard Institute for Space Studies in New York City.
Since 2014, Hansen has been leading a program at Columbia University. This program connects climate science with public awareness. It also encourages actions to deal with climate change. Hansen has even represented his granddaughter and "future generations" in a lawsuit. This lawsuit argues that the U.S. government should do more to protect a stable climate.
Important Research and Discoveries
As a student, James Hansen was very interested in science. He later focused on how human activities change the Earth's atmosphere. He wanted to understand how these changes affect our climate.
One of his main interests is studying how satellites can help us understand Earth's atmosphere. Satellites can see the whole planet. This makes them very useful for watching global changes. He also works on creating computer models to understand climate trends. He tries to figure out how humans are impacting the climate.
Studying Venus's Atmosphere
In the late 1960s and early 1970s, Hansen studied the planet Venus. Venus is very hot, and its surface is hidden by thick clouds. Hansen suggested that tiny particles in Venus's atmosphere were trapping the planet's heat. This made the surface extremely hot.
Later studies showed that Venus might have had liquid water billions of years ago. But a "runaway greenhouse effect" happened. This means that as the water evaporated, it created more greenhouse gases. This trapped even more heat, making Venus what it is today.
Hansen also studied what Venus's clouds were made of. He used the way sunlight reflected off the planet. He found that the clouds were spherical and made of sulfuric acid. This was a big discovery because many scientists had different ideas.
Research on Black Carbon
Hansen has also helped us understand black carbon. Black carbon is like soot, tiny dark particles released when things burn. In some parts of China, black carbon has caused changes in weather patterns. It can make the air hotter, leading to more rain in some areas and droughts in others.
Hansen and his team found that many climate models underestimated how much black carbon was in the air. They realized that black carbon has a bigger effect on warming than previously thought.
Black carbon emissions increased a lot after the Industrial Revolution. But in places like the United Kingdom, they have been going down since the 1960s. Hansen's research also showed that much of the black carbon in the Arctic comes from South Asia.
Human Impact on Climate
The United Nations Framework Convention on Climate Change is an international agreement. Its goal is to stop dangerous human activities from changing the climate too much.
In 2000, Hansen suggested that the warming over the last 100 years was mostly due to greenhouse gases other than carbon dioxide. These include gases like methane. He noted that the cooling effect from aerosols (tiny particles) had balanced out some of the warming from carbon dioxide. However, he also warned that carbon dioxide would become the main driver of warming in the future.
In 2003, Hansen wrote that human activities are now having a greater effect on the climate than natural forces. He said that this could lead to big climate changes over a long time. He also warned that the melting of the Greenland and Antarctic ice sheets could be a sign of "dangerous human interference." He believes that stopping global warming needs urgent international cooperation.
Hansen has also talked about how he was told by government officials not to discuss the dangerous effects of human influence on climate. He called this a "Faustian bargain." This means that while reducing aerosols is good for health, it could also increase warming from carbon dioxide.
Hansen and his co-authors believe that global temperature is a good way to measure dangerous human impact. They highlighted two major concerns: sea level rise and the extinction of species. They showed that if we continue as usual, sea levels could rise by 10 meters. This would be devastating for coastal areas. They also warned of much greater species extinction.
In 2007, Hansen clarified that a further warming of just 1°C would be very harmful to humans. He concluded that carbon dioxide levels above 450 ppm are dangerous. He urged quick action to slow carbon dioxide growth and prevent dangerous climate change.
Climate Model Development and Predictions
Scientists started developing climate models in the early 1900s. But progress was slow because computers were not powerful enough. Hansen made his first big contribution to climate models in 1974. His model was able to successfully show major weather patterns.
In 1981, Hansen and his team published a paper. They predicted that carbon dioxide in the atmosphere would cause warming sooner than expected. They used a simpler model that calculated temperature at different heights. Hansen predicted that temperatures would clearly rise above natural changes by the 1990s. He also thought it would be hard to convince politicians and the public to act.
By the early 1980s, computers were faster. Climate models became more detailed. Hansen's team could run their model for five years. They showed that the global climate could be simulated well even with a large grid.
Hansen published his first climate prediction from a full climate model in 1988. This was the same year he gave his famous speech to the U.S. Senate. He used his model to estimate how much the average surface temperature would change. He looked at different scenarios for future greenhouse gas emissions. Hansen concluded that global warming would be clear within a few decades. He said that if the temperature rose 0.4°C above the 1950–1980 average for a few years, it would be clear that humans were causing global warming.
In 2006, Hansen and his team compared their 1988 predictions with actual observations. They found that the real-world greenhouse gas levels were closest to their "intermediate" scenario. They noted that the observed warming matched their predictions well.
A year later, Hansen and other scientists compared climate predictions with observations from 1990 to 2007. They found that the climate system might be reacting faster than the models showed. They were concerned that sea levels were rising at the higher end of predictions. This was mainly due to the ocean expanding as it got warmer.
In 1990, other scientists published satellite temperature measurements. These initially showed a cooling trend, which was different from climate models. But in 1998, scientists found an error in the satellite data. Once corrected, the satellite data matched Hansen's model well. Hansen noted that this correction meant the debate would shift. It would no longer be about if global warming was happening, but how fast and what to do about it.
Hansen continues to develop and improve climate models. The current version of his model, called Model E, has many improvements. It helps scientists understand how human actions affect the climate.
Climate Forcings, Feedbacks, and Sensitivity
In 2000, Hansen wrote about a more hopeful way to deal with global warming. He suggested focusing on reducing non-carbon dioxide gases and black carbon first. This would give more time to reduce fossil fuel emissions. He pointed out that non-carbon dioxide gases were responsible for about half of the human-caused greenhouse gas warming at that time.
In 2007, Hansen discussed the danger of "fast-feedback" effects. These are quick changes that can cause ice sheets to break apart. He looked at past climate data. He noted that ice at the poles does not melt slowly and steadily. Instead, it can change suddenly. For example, millions of years ago, when temperatures were 2-3°C warmer, sea levels rose by 25 meters, not just a few centimeters.
Hansen stressed that it's hard to predict exactly when these sudden changes might happen. But he believes that ice sheets could respond in centuries, or even decades, once they start melting widely. He concluded that the "dangerous level" of human-made greenhouse gases is much lower than people thought. He warned that if we haven't already passed it, we will soon.
In 2013, Hansen published a paper estimating how sensitive the climate is to carbon dioxide. He found that if carbon dioxide doubles, the temperature could rise by about 3°C. He also warned that burning all fossil fuels would make most of the planet too hot for humans to live in.
In 2016, Hansen led a team of 19 researchers. They published a paper about how melting ice affects ocean currents. This could speed up ice sheet melting and sea level rise. It could also lead to stronger storms, like those seen millions of years ago.
In 2023, Hansen and his team published another paper. They concluded that if carbon dioxide doubles, the Earth's temperature could rise by about 4.8°C. This is much higher than earlier estimates. They also warned that reducing air pollution (which includes aerosols that cool the planet) will make global warming happen faster. They predicted that the world could pass the 1.5°C warming limit before 2030. They also said that a major ocean current system could collapse before the end of the century.
Climate Change Activism
Speaking to the U.S. Senate
James Hansen was asked to speak to the United States Senate Committee on Energy and Natural Resources on June 23, 1988. He told them that global warming had reached a point where scientists could be very sure that greenhouse gases were causing the warming. He said, "It is already happening now."
Many people believe Hansen's speech was a turning point. It helped more people become aware of climate change. It also started a big public discussion about what to do about global warming.
Carbon Tax Idea
In 2009, Hansen spoke out against a system called "cap and trade." Instead, he supported a "carbon tax." This means putting a fee on carbon at its source, like oil, gas, or coal. Then, all the money collected would be given back to citizens in equal shares. He has supported the work of the Citizens' Climate Lobby, which promotes this idea.
Retirement from NASA
Hansen retired from NASA in April 2013 after 46 years. He said he wanted to spend more time working on political and legal efforts to limit greenhouse gases. After retiring, he also became an advisor to an organization that supports teaching climate change in schools.
Keystone Pipeline Protest
In 2013, Hansen strongly spoke against the Keystone pipeline extension. This pipeline was planned to carry oil from Canada's oil sands to the Gulf of Mexico. Hansen argued that using these types of fossil fuels would release too much carbon. He said that the effects of climate change might not be fully seen for many decades. He urged President Obama to reject the pipeline. On February 13, 2013, Hansen was arrested at the White House during a protest against the pipeline.
Ideas for Solutions
Hansen supports a system where a fee is placed on carbon. The money collected from fossil fuel companies would then be given back to all legal residents. He believes this would make the true costs of fossil fuels clear. He says that right now, the public pays for the health and environmental problems caused by fossil fuels.
In 2008, Hansen suggested five main actions for leaders to take. These included using energy wisely, using renewable energy, building a "smart grid" for electricity, and developing advanced nuclear reactors. He also supported capturing and storing carbon dioxide from power plants.
In 2009, Hansen wrote an open letter to President Obama. He suggested stopping new coal power plants that don't capture and store carbon dioxide. In his book, Storms of My Grandchildren, he also supported this idea.
In 2013, Hansen co-authored a paper about nuclear power. The paper suggested that nuclear power has prevented many deaths from air pollution. It also said that nuclear power has avoided billions of tonnes of carbon dioxide emissions. However, other scientists have criticized this paper. They argue that nuclear power is expensive and has safety concerns.
Despite the debate, Hansen and other climate experts have written open letters. They say that opposing nuclear power makes it harder to avoid dangerous climate change. Hansen has also traveled the world to explain the benefits of nuclear energy for the climate.
Concerns about Political Interference
In 2006, Hansen said that NASA officials tried to control what he said publicly about climate change. He claimed that his statements were reviewed after a speech he gave in 2005. NASA responded that it was standard policy for employees to coordinate statements with the public affairs office. However, two years later, an investigation confirmed that NASA's public affairs office had "reduced, marginalized or mischaracterized climate change science."
In June 2006, Hansen appeared on a TV show called 60 Minutes. He said that the White House had changed press releases about climate. This made global warming seem less serious. He also said he felt he couldn't speak freely without problems from government officials. He had not experienced such restrictions before in his career.
Calling for Accountability
In 2008, Hansen suggested that leaders of fossil fuel companies should be held responsible. He said that these companies had spread doubt and false information about global warming. He compared this to how tobacco companies tried to hide the link between smoking and cancer.
Arrest at a Demonstration
In August and September 2011, James Hansen was arrested at a protest outside the White House. He was among 1,251 activists. They were protesting against the Keystone pipeline extension. On February 13, 2013, Hansen was arrested again at the White House during another protest against the pipeline.
Honors and Awards
James Hansen was chosen to be part of the United States National Academy of Sciences in 1996. This was for his important work on climate models and understanding climate change. In 2001, he received the Heinz Award in the Environment for his research on global warming.
In 2006, Time magazine named him one of the 100 Most Influential People. Also in 2006, he received an award for his "courageous and steadfast advocacy" in sharing scientific findings openly.
In 2007, Hansen shared the Dan David Prize, worth US$1 million. In 2008, he received the PNC Bank Common Wealth Award for his achievements in science. He was also named Scientist Communicator of the Year in 2008 for explaining science to the public.
In 2009, Hansen received the Carl-Gustaf Rossby Research Medal. This is the highest honor from the American Meteorological Society. It was for his work on climate modeling and for clearly explaining climate science to the public.
Hansen won the 2010 Sophie Prize. This prize was created by the author of the book Sophie's World. He won it for his "key role" in helping us understand human-caused climate change.
Foreign Policy magazine named Hansen one of its Top 100 Global Thinkers in 2012. This was for "sounding the alarm on climate change, early and often." In December 2012, he received an award for outstanding climate science communication.
On November 7, 2013, Hansen received the Joseph Priestley Award. This was for his work in understanding climate change and for helping the public understand it.
James Hansen shared the BBVA Foundation Frontiers of Knowledge Award in 2016. He shared it with another scientist, Syukuro Manabe. Both scientists created the first computer models that could predict climate behavior. Their models correctly predicted how much Earth's temperature would rise due to increasing carbon dioxide.
In June 2018, Hansen was a joint winner of Taiwan's Tang Prize.
See also
In Spanish: James Hansen para niños
