Well, if we cannot control the weather, why do we keep pretending we can? Seems every story and many political campaigns are premised upon the fiction that we can control “climate change,” if we want.
Global Climate Changes
- Thread starter Caveman Catfan
- Start date
Natural increases in carbon dioxide concentrations have periodically warmed Earth’s temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth’s orbit around the Sun and its axis of rotation. (For more details, see the “Milankovitch cycles and ice ages” section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide—like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.
Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.
Atmospheric carbon dioxide (CO2) in parts per million (ppm) for the past 800,000 years based on ice-core data (light purple line) compared to 2022 concentration (bright purple dot). The peaks and valleys in the line show ice ages (low CO2) and warmer interglacials (higher CO2). Throughout that time, CO2 was never higher than 300 ppm (light purple dot, between 300,000 and 400,000 years ago). The increase over the last 60 years is 100 times faster than previous natural increases. In fact, on the geologic time scale, the increase from the end of the last ice age to the present (dashed purple line) looks virtually instantaneous. Graph by NOAA Climate.gov based on data from Lüthi, et al., 2008, via NOAA NCEI Paleoclimatology Program.
By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was roughly 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5–7.2 degrees Fahrenheit (2.5–4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.
If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher—conditions not seen on Earth for close to 50 million years.
www.climate.gov
Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.
Atmospheric carbon dioxide (CO2) in parts per million (ppm) for the past 800,000 years based on ice-core data (light purple line) compared to 2022 concentration (bright purple dot). The peaks and valleys in the line show ice ages (low CO2) and warmer interglacials (higher CO2). Throughout that time, CO2 was never higher than 300 ppm (light purple dot, between 300,000 and 400,000 years ago). The increase over the last 60 years is 100 times faster than previous natural increases. In fact, on the geologic time scale, the increase from the end of the last ice age to the present (dashed purple line) looks virtually instantaneous. Graph by NOAA Climate.gov based on data from Lüthi, et al., 2008, via NOAA NCEI Paleoclimatology Program.
By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was roughly 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5–7.2 degrees Fahrenheit (2.5–4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.
If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher—conditions not seen on Earth for close to 50 million years.
Climate Change: Atmospheric Carbon Dioxide
In the past 60 years, carbon dioxide in the atmosphere has increased 100 times faster than it did during the end of the last ice age.
