Climate is accumulating 4 Hiroshima atomic bombs worth of heat per second

The earth's climate system absorbs heat in many different ways. Increases in the temperatures that people experience day to day are only one of several reservoirs for accumulating heat. While changes in the atmosphere are the easiest to recognize, they are also the most variable and subject to “noise”. Changes in the ocean, where most of the heat is going, have been more steady, while the melting of vast stores of ice is accelerating. The earth continues to warm, day after day, at a concerning rate.

Ocean Atmosphere Land Melting Ice Trends

When the energy from all of the earth's “heat” reservoirs is combined, the clear, decades long trend is unequivocal and staggering. With the exception of short “hiatus” periods, the earth has been gaining heat, virtually continuously, at an average rate of 250 trillion Joules per second, and this trend shows no serious sign of ending.

Without greenhouse gases, the temperature at the surface of the earth would be a mere -15°C (5°F). Life on earth is made possible by greenhouse gases.

The earth's atmosphere is mostly transparent to incoming sunlight, which passes through and warms the surface of the earth. Warm objects in turn emit another wavelength of light, one invisible to the human eye, termed “infrared radiation”. Like visible light, infrared radiation passes through the atmosphere and into space.

But small traces of greenhouse gases, such as carbon dioxide, are not transparent to infrared radiation. They absorb and re-emit that energy, trapping some of that heat within the atmosphere.

Changes in the climate are visible all around us. Some are subtle and seemingly inconsequential, but these changes are accelerating and undeniable.

Spring comes earlier. Tree lines and species are migrating poleward and upward. Glaciers and Arctic ice are retreating at an alarming rate4. Sea levels are rising5. Every day, more and more studies point towards a changing and warming world in new and sometimes unexpected ways.

The indicators that recent climate change is the result of burning fossil fuels, rather than from some unknown natural variation, are clear and consistent with what we do know.

There are subtle differences to how the world will warm due to greenhouse gases compared with other potential sources (such as an increase in the warmth of the sun). Most importantly, scientists know that greenhouse gases would cause the upper atmosphere to cool rather than warm.

We also know that the source of the additional carbon dioxide in the atmosphere is due to burning fossil fuels. The carbon in fossil fuels differs from atmospheric carbon because it has less of the isotope known as 13C (Carbon-13), a heavier-than-normal version of carbon. Plants generally prefer the lighter and more common 12C (Carbon-12) for photosynthesis, so fossil fuels, which are produced from decayed plant matter, are deficient in 13C. As a result, when we burn fossil fuels we cause the percentage of 13C in the atmosphere to drop, and this change has been detected.

Scientists have established that climate change greater than 2°C (4°F) will likely be extremely dangerous. We are likely to have committed our planet to that degree of warming when atmospheric carbon dioxide concentrations reach 450 ppm (parts per million). The natural, pre-industrial level of carbon dioxide (CO2) was around 285 ppm. The level of CO2 is currently near 400 ppm.

That level of carbon dioxide, 400 ppm, has not been seen in the atmosphere for millions of years.

At the current rate, adding 2 ppm per year, we will reach 450 ppm around the year 2038, a mere 25 years from now.

Not all effects of climate change can be anticipated, and not all effects that are anticipated may come to pass, but the number of expected, negative impacts on human society present a clear and worrying danger.28 Some of these impacts are already being felt, to varying degrees, although many will not seriously present themselves until temperatures increase by 2°C or more (although we have already committed to more than 1.4°C of warming, depending on actual climate sensitivity).

It is important to realize that no matter how strong these impacts are felt now, they will grow worse over time, and when they do, we will have no ability to reverse any of them.

More than 90% of all heat being absorbed by the earth, each and every day, is going into the oceans.

The ocean, when viewed from a climate perspective, is often considered in three layers:

The surface to 700 meters down.

700 meters to 2000 meters down.

2000 meters down to the bottom (average is about 3800 meters).

For some time, scientists believed that ocean warming would be restricted to the upper 700 meters and that global warming would take a very long time to penetrate deeper than that. Recent studies2 and modern measurement techniques have shown, however, that the ocean below 700 meters is heating as well, and the amount of energy that it takes to do so is staggerring.

Scientists2 use ocean heat content measurements from ARGO floats, as well as data from expendable bathythermographs (XBT) and mechanical bathythermographs (MBT).

Argo is an international project to collect information on the temperature and salinity of the upper part of the world's oceans. Argo uses robotic floats that spend most of their life drifting below the ocean surface, reaching depths of 2000m and spending periods of approximately 10 days below the surface. Floats take temperature and salinity measurements as they rise to the surface. After surfacing they transmit their data to satellites and then submerge to repeat the data collection cycle. Currently, there are roughly 3000 floats producing 100,000 temperature/salinity profiles per year.

A bathythermograph is an instrument which has a temperature sensor and is thrown overboard from ships to record pressure and temperature changes as it drops through the water. These were the main instruments used to measure OHC before the ARGO float network was deployed starting about a decade ago to provide more accurate and consistent data.

The ocean accounts for more than 90% of the heat absorbed by the earth in the past 30 years.

The total increase in heat content of the oceans over the period from 1955-2010 was 24 x 1022 (240,000,000,000,000,000,000,000) Joules.

The energy absorbed by the oceans will not quickly dissipate.

As the ocean warms it expands, leading to marked sea level rise.

Increased ocean temperatures help to warm the atmosphere.

Increased ocean temperatures help to generate and intensify storms.

Warmer waters, combined with ocean acidification, are pushing some forms of marine life beyond their limits.

Changes in the temperature of the earth's atmosphere are the easiest to measure and the most obvious in an individual's personal experience, but the atmosphere is also the most variable. One very warm year can be followed by several cold ones, while one region may experience an unusual cold snap while many other parts of the globe endure record warmth. Many factors can influence global atmospheric temperatures over short time frames of a few years, which in turn disguises the insistent, uninterrupted warming which is occurring overall.

Nevertheless, the atmosphere has warmed by 0.8°C (1.4°F) in the past century. This warming is more exaggerated at the poles, leading to even greater swings in temperatures further from the equator. Yet it still accounts for only 2% of total heat absorbed by the earth's climate.

Scientists and statisticians have worked together to try to quantify and eliminate the most obvious forms of variability in global atmospheric temperatures by using standard statistical methods. In one study6, the authors found that after removing the influence of the most significant three factors (ENSO events, solar variations, and aerosols) the seemingly chaotic, drunken meanderings of the earth's temperature straightened into a clear, steady increase in global temperatures.

In particular, in the past decade, a quiet sun, an increase in La Niña (cold) events, and an increase in aerosols have worked to temporarily slow global warming. This sort of hiatus period is often seen in climate models, when negative factors happen to combine to temporarily overwhelm the global warming signal. It is clear, however, from the evidence that any respite is temporary.

The atmosphere, ocean, land and ice continue to absorb heat, and global warming is going to continue well into our future.

The Pacific is not only the world's largest ocean, but it also boasts by far the largest expanse of water along the equator, where the sun's rays are strongest. Periodic events, termed El Niño and La Niña, lead to three common states in the equatorial regions of the Pacific. These states in turn affect air temperatures and precipitaiton around the globe, and so are keys to understanding and predicting short-term climate variations.

El Niño events denote the spread of warmer than usual waters across much of the equatorial Pacific. This raises temperatures globally.

La Niña events denote the piling up of warmer waters in the western Pacific and the spread of cooler than usual waters across the eastern Pacific, off the coast of South America. This reduces temperatures globally.

ENSO neutral conditions, when neither an El Niño nor a La Niña is present, is the third state.

One way to view temperature changes without the confusing influences of ENSO events is to compare apples to apples. Compare all El Niño events to each other, La Niña to each other, and neutral conditions. When this is done, again, the constant, upward trend in global temperatures becomes clear.

The sun supplies virtually all of the energy that fuels the earth's climate, but changes in solar activity are necessary to account for changes in the earth's climate. While the sun did warm slightly in the early part of the Twentieth century, it has since begun to quiet again. These minor changes in solar output, however, are not nearly strong enough to account for warming this century, although they do contribute somewhat to dampening recent anthropogenic warming. A “hot” sun, for example, emits roughly 1367 Watts/meter2, while a “cool” sun emits 1365.5 Watts/meter2, a difference between “hot” and “cold” of only about one tenth of one percent.

One study7 used a statistical test on the temperature data, and found that while solar activity can account for about 11% of the global warming from 1889 to 2006, it can only account for 1.6% of the warming from 1955 to 2005, and had a slight cooling effect (-0.004°C per decade) from 1979 to 2005. Multiple other studies 6 8 9 confirm this conclusion.

Volcanoes emit sulfate aerosols which reflect incoming sunlight, cooling the planet. A large volcanic eruption such as the Pinatubo eruption in 1991 can have a global cooling effect of 0.1°–0.3°C (0.18°–0.54°F) for several years 10.

However, mega-eruptions or a series of eruptions can have a cooling effect that take decades to wear off, giving a perceived warming effect as temperatures return to normal. Scientists have studied past volcanoes11, particularly over the past few centuries, and found that early 20th century warming resulted, in part, from a recovery from earlier periods of heavy vulcanism. In short, a lack of volcanic activity had some part in temperature rise over the first half of the 20th century. However, it has played little part in the modern global warming trend that began in the 1970s.

More recently, in the past decade, scientists12 have found that the increase in greenhouse gases was exceeded by an even greater increase in sunlight-reflecting sulfate aerosols, which originate from the rapid industrialization of China. Chines