Annals of Global Warming: Planetary energy budget, for beginners, and climate engineering — from GAO


From the General Accountability Office, an arm of Congress, a report to the House Committee on Science, Space and Technology.

Aug 25, 2011
01:16

Global Average Energy Budget of the Earth’s Atmosphere

In eight steps, this animation depicts the path of sunlight that enters the planet’s atmosphere, illustrating how that radiation is reflected, absorbed, and emitted as heat energy.

In less than 90 seconds, an animated, graphic description of how and why global warming occurs.  You didn’t get it in 90 seconds?  Watch it again.  This video was made to accompany a GAO report on climate engineering. (Emphasis added, in red.)

Climate Engineering: Technical Status, Future Directions, and Potential Responses

GAO-11-71, Aug 25, 2011

[135-page report, in .pdf, here]

Summary:  Reports of rising global temperatures have raised questions about responses to climate change, including efforts to (1) reduce carbon dioxide (CO2) emissions, (2) adapt to climate change, and (3) design and develop climate engineering technologies for deliberate, large-scale intervention in Earth’s climate. Reporting earlier that the nation lacks a coordinated climate-change strategy that includes climate engineering, GAO now assesses climate engineering technologies, focusing on their technical status, future directions for research on them, and potential responses. To perform this technology assessment, GAO reviewed the peer-reviewed scientific literature and government reports, consulted experts with a wide variety of backgrounds and viewpoints, and surveyed 1,006 adults across the United States. Experts convened with the assistance of the National Academy of Sciences advised GAO, and several reviewed a draft of this report. GAO incorporated their technical and other comments in the final report as appropriate.

Climate engineering technologies do not now offer a viable response to global climate change. Experts advocating research to develop and evaluate the technologies believe that research on these technologies is urgently needed or would provide an insurance policy against worst case climate scenarios–but caution that the misuse of research could bring new risks. Government reports and the literature suggest that research progress will require not only technology studies but also efforts to improve climate models and data. The technologies being proposed have been categorized as carbon dioxide removal (CDR) and solar radiation management (SRM). CDR would reduce the atmospheric concentration of CO2, allowing more heat to escape and thus cooling the Earth. For example, proposed CDR technologies include enhancing the uptake of CO2 in oceans and forests and capturing CO2 from air chemically for storage underground. SRM technologies would place reflective material in space or in Earth’s atmosphere to scatter or reflect sunlight (for example, by injecting sulfate aerosols into the stratosphere to scatter incoming solar radiation or brightening clouds) or would increase the planet’s reflectivity (for example, by painting roofs and pavements in light colors). GAO found these technologies currently immature, many with potentially negative consequences. Some studies say, for example, that stratospheric aerosols might greatly reduce summer precipitation in places such as India and northern China. Many experts advocated research because of its potential benefits but also recognized its risks. For example, a country might unilaterally deploy a technology with a transboundary effect. Research advocates emphasized the need for risk management, envisioning a federal research effort that would (1) focus internationally on transparency and cooperation, given transboundary effects; (2) enable the public and national leaders to consider issues before they become crises; and (3) anticipate opportunities and risks. A small number of those we consulted opposed research; they anticipated major technology risks or limited future climate change. Based on GAO’s survey, a majority of U.S. adults are not familiar with climate engineering. When given information on the technologies, they tend to be open to research but concerned about safety.

Transcript of the video, describing each slide, below the fold.

From the U.S. Government Accountability Office, http://www.gao.gov

Title: Global Average Energy Budget of the Earth’s Atmosphere

Description: In eight steps, this animation depicts the path of sunlight that enters the planet’s atmosphere, illustrating how that radiation is reflected, absorbed, and emitted as heat energy. (No audio.)

Related GAO Work: GAO-11-71, Climate Engineering: Technical Status, Future Directions, and Potential Responses

Issue date: July 28, 2011

[First screen]
This screen has the GAO logo and the following text: “Global Average Energy Budget of the Earth’s Atmosphere,” “Animation to GAO-11-71,” “Climate Engineering: Technical Status, Future Directions, and Potential Responses.”

[Second screen]
This screen title, in a gray box at the bottom of the screen, reads: “1. Incoming sunlight.” Also in the gray box it notes that “All values are global averages in watts per square meter.” The screen depicts a landscape including a sun, black outer space, a white outer atmosphere, a blue sky with two clouds, and a green earth. A yellow ray emerges from the sun in the direction of the Earth with the following label:  “Incoming sunlight 342 watts per square meter.”

[Third screen]
This screen title, in a gray box at the bottom of the screen, reads: “2. Sunlight reflected from and absorbed by atmosphere and clouds.” Also in the gray box it notes that “All values are global averages in watts per square meter.” The yellow ray of sunlight splits off into two smaller rays. One ray extends into the outer atmosphere and is labeled:  “Reflected from atmosphere and clouds, 77 watts per square meter.” The other ray points sideways across the sky and is labeled: “Absorbed by atmosphere and clouds, 67 watts per square meter.”

[Fourth screen]
This screen title, in a gray box at the bottom of the screen, reads: “3. Sunlight absorbed by Earth’s surface.” Also in the gray box it notes that “All values are global averages in watts per square meter.” Another ray emerges from the initial ray, this one extending all the way to the green surface of the Earth. This ray has the following label: “Absorbed by Earth’s surface, 168 watts per square meter.”

[Fifth screen]
This screen title, in a gray box at the bottom of the screen, reads: “4. Sunlight reflected from Earth’s surface.” Also in the gray box it notes that “All values are global averages in watts per square meter.” A thin ray emerges from the last ray, extending up into the sky. This ray has the following label: “Reflected from Earth’s surface, 30 watts per square meter.”

[Sixth screen]
This screen title, in a gray box at the bottom of the screen, reads: “5. Energy transferred to atmosphere by evaporation and emitted as heat energy.” Also in the gray box it notes that “All values are global averages in watts per square meter.” Two new rays emerge from the Earth’s surface and extend into the sky. One is a thin green ray, stopping about half way to the outer atmosphere, positioned in the center of the screen and labeled: “Transferred from Earth’s surface by evaporation and convection.” A slightly wider red ray, stopping just short of the outer atmosphere, is on the right side of the screen and is labeled: “Emitted from Earth’s surface.”

[Seventh screen]
This screen title, in a gray box at the bottom of the screen, reads: “6. Heat energy from Earth absorbed by atmosphere and clouds and escapes to space.” Also in the gray box it notes that “All values are global averages in watts per square meter.” Two red rays extend from the red ray that appeared on the right side of the screen in the previous slide.  A very thin one extends towards outer space and is labeled, “Emitted directly to space.” A slightly wider red ray extends horizontally across the sky and is labeled “Absorbed by atmosphere and clouds.” Additionally, a white oval appears in the sky and is labeled “Atmosphere and clouds.”

[Eighth screen]
This screen title, in a gray box at the bottom of the screen, reads: “7. Energy absorbed by atmosphere and clouds emitted as heat energy back to Earth and out to space.” Also in the gray box it notes that “All values are global averages in watts per square meter.” Two red rays emerge from the white oval labeled “Atmosphere and clouds” that appeared in the previous slide. One extends up towards outer space and the other extends down to the Earth’s surface. Both are labeled “Emitted from atmosphere and clouds.”

[Ninth screen]
This screen title, in a gray box at the bottom of the screen, reads: “8. The Greenhouse Effect: Earth’s temperature modified by energy absorbed by and emitted from atmosphere and clouds.” Also in the gray box it notes that “All values are global averages in watts per square meter.” All the red rays and the green ray expand in width. A value appears next to each label, listed in order of when they first appeared, as follows:

Green ray extending from Earth’s surface: “Transferred from Earth’s surface by evaporation and convection, 102 watts per square meter.”

Red ray extending from Earth’s surface: “Emitted from Earth’s surface, 390 watts per square meter.”

Red ray extending towards outer space: “Emitted directly to space, 40 watts per square meter.”

Red ray extending horizontally across the sky: “Absorbed by atmosphere and clouds 350 watts per square meter.”

Red ray extending from the white oval labeled “Atmosphere and clouds” up and into outer space: “Emitted from atmosphere and clouds, 195 watts per square meter.”

Red ray extending from the white oval labeled “Atmosphere and clouds” down to the Earth’s surface: “Emitted from atmosphere and clouds, 324 watts per square meter.”

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