<=>Biosphere
Meanwhile the level of CO2 in the air kept rising, indeed faster than anyone had expected. Ever since the late 1950s, an increasing number of experts had been saying that effects on climate would become clearly visible around the year 2000. They were right. As the 21st century began, not only was the global temperature soaring in a way never seen before, but field evidence showed that the expected feedbacks were kicking in. The world's plants were taking up more CO2, but many ecosystems were under stress and their capacity to absorb was waning. Warmer oceans were absorbing less CO2, and gas was seen bubbling from melting Arctic tundra.(60) In sum, global warming was leading to more greenhouse emissions, which would lead to more warming... and so forth. Also as predicted, the world was beginning to suffer worse heat waves, droughts, floods, and severe storms, while the sea level rose and important ecosystems began to show signs of stress. (See the essay on impacts). For the scientists, as one of them remarked, "Seeing their own predictions come true has been a frightening experience."(61)
<=Biosphere
=>Modern temp's
=>Climate cycles
Still more sobering, people were just now coming to grips with the implications of a fact that scientists had known for decades — the climate system has built-in time lags. Even if human emissions of CO2 magically dropped to zero, the gas already in the air would linger for many centuries, trapping heat. Global temperatures would continue to creep upward until the ocean depths reached equilibrium with the heated air, until biological systems finished adapting to the new conditions, and until Arctic icecaps melted back to their own equilibrium. Whatever we did now, humanity was already committed to centuries of changing weather and rising seas.(62*) Yet emissions of greenhouse gases, far from halting, were soaring at an accelerating rate.
The basic physics and chemistry of the problems raised by Tyndall were now well in hand. There were reliable calculations of the direct effects of CO2 on radiation, of how the gas was dissolved in sea water, and other physical phenomena. Further progress would center on understanding the complex interactions of the entire planetary system, and especially interactions with living creatures. The creatures who would count the most were humans. The climate a century hence would depend chiefly on what they chose to do about their emissions.
If the planet warmed up by several several degrees during the 21st century, as paleontologists and computer modelers agreed was likely, what would be the consequences? This became the new center for much of the research. Extensive studies showed that the consequences of a two degree rise would be severe in many parts of the world — and such a rise was more likely than not by the late 21st century, even if governments woke up to the danger and began to restrict greenhouse gas emissions. And if we did not act promptly and forcefully to shut down emissions? It was even odds that by the end of the century we would face an unprecedented and catastrophic collapse of many of the ecosystems on which civilization depends.
See the summary of expected Impacts of Global Warming
<=>Biosphere
Meanwhile the level of CO2 in the air kept rising, indeed faster than anyone had expected. Ever since the late 1950s, an increasing number of experts had been saying that effects on climate would become clearly visible around the year 2000. They were right. As the 21st century began, not only was the global temperature soaring in a way never seen before, but field evidence showed that the expected feedbacks were kicking in. The world's plants were taking up more CO2, but many ecosystems were under stress and their capacity to absorb was waning. Warmer oceans were absorbing less CO2, and gas was seen bubbling from melting Arctic tundra.(60) In sum, global warming was leading to more greenhouse emissions, which would lead to more warming... and so forth. Also as predicted, the world was beginning to suffer worse heat waves, droughts, floods, and severe storms, while the sea level rose and important ecosystems began to show signs of stress. (See the essay on impacts). For the scientists, as one of them remarked, "Seeing their own predictions come true has been a frightening experience."(61)
<=Biosphere
=>Modern temp's
=>Climate cycles
Still more sobering, people were just now coming to grips with the implications of a fact that scientists had known for decades — the climate system has built-in time lags. Even if human emissions of CO2 magically dropped to zero, the gas already in the air would linger for many centuries, trapping heat. Global temperatures would continue to creep upward until the ocean depths reached equilibrium with the heated air, until biological systems finished adapting to the new conditions, and until Arctic icecaps melted back to their own equilibrium. Whatever we did now, humanity was already committed to centuries of changing weather and rising seas.(62*) Yet emissions of greenhouse gases, far from halting, were soaring at an accelerating rate.
The basic physics and chemistry of the problems raised by Tyndall were now well in hand. There were reliable calculations of the direct effects of CO2 on radiation, of how the gas was dissolved in sea water, and other physical phenomena. Further progress would center on understanding the complex interactions of the entire planetary system, and especially interactions with living creatures. The creatures who would count the most were humans. The climate a century hence would depend chiefly on what they chose to do about their emissions.
If the planet warmed up by several several degrees during the 21st century, as paleontologists and computer modelers agreed was likely, what would be the consequences? This became the new center for much of the research. Extensive studies showed that the consequences of a two degree rise would be severe in many parts of the world — and such a rise was more likely than not by the late 21st century, even if governments woke up to the danger and began to restrict greenhouse gas emissions. And if we did not act promptly and forcefully to shut down emissions? It was even odds that by the end of the century we would face an unprecedented and catastrophic collapse of many of the ecosystems on which civilization depends.
See the summary of expected Impacts of Global Warming
<=>Biosphere
Meanwhile the level of CO2 in the air kept rising, indeed faster than anyone had expected. Ever since the late 1950s, an increasing number of experts had been saying that effects on climate would become clearly visible around the year 2000. They were right. As the 21st century began, not only was the global temperature soaring in a way never seen before, but field evidence showed that the expected feedbacks were kicking in. The world's plants were taking up more CO2, but many ecosystems were under stress and their capacity to absorb was waning. Warmer oceans were absorbing less CO2, and gas was seen bubbling from melting Arctic tundra.(60) In sum, global warming was leading to more greenhouse emissions, which would lead to more warming... and so forth. Also as predicted, the world was beginning to suffer worse heat waves, droughts, floods, and severe storms, while the sea level rose and important ecosystems began to show signs of stress. (See the essay on impacts). For the scientists, as one of them remarked, "Seeing their own predictions come true has been a frightening experience."(61)
<=Biosphere
=>Modern temp's
=>Climate cycles
Still more sobering, people were just now coming to grips with the implications of a fact that scientists had known for decades — the climate system has built-in time lags. Even if human emissions of CO2 magically dropped to zero, the gas already in the air would linger for many centuries, trapping heat. Global temperatures would continue to creep upward until the ocean depths reached equilibrium with the heated air, until biological systems finished adapting to the new conditions, and until Arctic icecaps melted back to their own equilibrium. Whatever we did now, humanity was already committed to centuries of changing weather and rising seas.(62*) Yet emissions of greenhouse gases, far from halting, were soaring at an accelerating rate.
The basic physics and chemistry of the problems raised by Tyndall were now well in hand. There were reliable calculations of the direct effects of CO2 on radiation, of how the gas was dissolved in sea water, and other physical phenomena. Further progress would center on understanding the complex interactions of the entire planetary system, and especially interactions with living creatures. The creatures who would count the most were humans. The climate a century hence would depend chiefly on what they chose to do about their emissions.
If the planet warmed up by several several degrees during the 21st century, as paleontologists and computer modelers agreed was likely, what would be the consequences? This became the new center for much of the research. Extensive studies showed that the consequences of a two degree rise would be severe in many parts of the world — and such a rise was more likely than not by the late 21st century, even if governments woke up to the danger and began to restrict greenhouse gas emissions. And if we did not act promptly and forcefully to shut down emissions? It was even odds that by the end of the century we would face an unprecedented and catastrophic collapse of many of the ecosystems on which civilization depends.
See the summary of expected Impacts of Global Warming
The Carbon Dioxide Greenhouse Effect
