Human emissions of carbon dioxide and other greenhouse gases have fundamentally changed the makeup of Earth's atmosphere.
Cheap energy has been crucial in developing modern civilization. The advances in technology, medicine, science, and much more can hardly be quantified. However, fossil fuel energy has a darker side that is becoming more apparent with each passing year.
Fossil fuels are comprised of carbon that has been locked away from the biosphere for millions of years. As we burn that carbon, it is emitted into the air as carbon dioxide. Measurements show that carbon dioxide levels have already risen about 47% since the Industrial Revolution.
This buildup of carbon dioxide is unlike any other in the paleoclimate record.
From ice cores in Greenland and Antarctica, we have excellent paleoclimate data for the past 800,000 years.
In the entire ice core record, there is nothing remotely like this sudden spike in carbon dioxide or other greenhouse gases.
This graph examines the past 10,000 years since the last ice age ended. Carbon dioxide was quite stable at 260 parts per million (ppm) to 280 ppm. In a geological eyeblink, it has spiked to well over 400 ppm.
This buildup of carbon dioxide is unlike any other in the paleoclimate record.
This graph displays the entire ice core record: all 800,000 years.
Carbon dioxide levels remained between 180 ppm and 300 ppm. Temperatures marched in lock step with variations in carbon dioxide: when carbon dioxide was low, an ice age resulted. When carbon dioxide was high, that defined an interglacial period.
Now, in a geological eyeblink, carbon dioxide has spiked to well over 400 ppm.
As a result, the oceans are acidifying.
Most people are familiar with the tangy, acidic taste of carbonated beverages. This results from a very simple chemical reaction: carbon dioxide reacts with water to produce carbonic acid.
This same principle is at work in the oceans. As we add carbon dioxide to the atmosphere, much of that carbon dioxide gets dissolved into the oceans, which then become more acidic.
Already the oceans have become about 30% more acidic than they were before the Industrial Revolution. This has significant repercussions for marine life, from plankton to shellfish to crabs to fish, to every part of the marine food web.
This graph shows this ongoing acidification in blue. Because the pH scale is logarithmic, the increase in acidity amounts to about 30%.
This buildup of greenhouse gases is heating the world.
Every published study arrives at the same conclusion: decade by decade, the world is warming.
The fossil fuel industry assembled a team of then-skeptical scientists and funded their independent study to determine if there was any room to cast doubt on this conclusion. Their scientists followed the evidence to essentially the same conclusion as NASA, NOAA, the Hadley Centre, the Japanese Meteorological Agency, and others. In fact, this is their own graph comparing their results with the results of other groups.
This warming event is unlike any other in the past 1,000 years.
Paleoclimatologists use tree rings, coral rings, ocean sediments, bore hole temperatures, stalagmites, ice cores, pollen, isotope analysis, and more to determine what prehistoric climate was like. Based on their findings, we know that this modern spike in warming is more significant and more abrupt than any other in the past 1,000 years.
This warming event is unlike any other in the past 20,000 years.
As we came out of the last ice age, the fastest rate of warming the world experienced was about 0.23 degrees C in 95 years.
With modern global warming, we've now warmed three times as much in less than half the time. Modern warming is far more abrupt than any the world has seen in 20,000 years.
Satellite measurements show the lower atmosphere is warming.
Satellites measure radiance of atmospheric oxygen, from which atmospheric temperature can be inferred. The results show warming comparable to the surface temperature record, though with greater uncertainty.
Arctic sea ice is in dramatic decline.
This graph shows every daily measurement of Arctic sea ice extent ever taken from satellite. The very light blue lines swing up and down by the season, and the gold line shows the 4-year running average.
In just 40 years, that 4-year running average has declined 16%, and the red line is on track for reaching essentially zero sea ice extent at the summer minimum by mid-century.
The trend in Antarctic sea ice is currently uncertain.
This graph shows every daily measurement of Antarctic sea ice extent ever taken from satellite. The very light blue lines swing up and down by the season, and the gold line shows the 4-year running average.
Up until 2014, Antarctic sea ice was slightly increasing, but since then it experienced a significant decline. Scientists are not yet certain what to expect for Antarctic sea ice extent in the near future.
The trend in global sea ice shows a dramatic decline.
Governed mostly by Arctic sea ice, and dramatically influenced by the recent drop in Antarctic sea ice, global sea ice levels have declined substantially.
Land ice is also in decline.
Antarctica is losing over 100 billion tons of land ice each year, and Greenland is losing nearly 300 billion tons of land ice each year.
Other mountain glaciers are losing around 400 billion tons each year.
Altogether, that adds up to about 8,000 cubic kilometers of land ice disappearing each decade.
Permafrost is thawing.
Across the world, permafrost temperatures are rising. Concurrently, the depth of summer thaw keeps increasing, as more and more permafrost reaches thawing temperatures each summer.