This book succinctly introduces ideas proposed by geoengineers to counteract climate change, and addresses each idea's benefits and risks. The author states the science of geoengineering is relatively new, and none of these ideas are in widespread use, although some, like cloud seeding, have been used for years metimes with disastrous results. Besides reforestation and switching to renewable and alternative fuels, bioengineers are working to create large-scale technologies like chemically thickening clouds to reduce the amount of sunlight reaching the ground, or placing giant mirrors in space to reflect sunlight away from the planet. The author emphasizes that many of these suggestions many be cost prohibitive, impractical, and have uncertain outcomes, and that from moral or ethical standpoints, not everyone agrees they should be used. Practical ways young people can help to reduce climate change now are appended, and graphs, color illustrations, source notes, glossary, and a selected bibliography are also included. This much-needed resource for this age group will be useful for student research.

How can we turn Earth's temperature down? An author of nonfiction for young readers on a wide range of topics takes on the controversial subject of geoengineering: purposeful human efforts at global climate change. With clear, information-packed exposition organized into short chapters and broken up with subheadings, diagrams, and photographs, she moves from a general overview and history to a consideration of two specific areas: carbon-dioxide removal and sun shields. She explains the greenhouse effect, the biological, industrial, and geological carbon cycles, photosynthesis, and the effects of ocean acidification and algal blooms. She talks about the importance of balance: avoiding efforts that will tip the climate from too warm to too cold. She points out the possibility that large-scale solar-radiation management could lead to a de-emphasis on reducing the amount of greenhouse gases being added to the atmosphere. Most importantly, she states that these global solutions are extremely controversial. Methods suggested so far would be expensive, possibly wildly impractical, and likely to have unintended consequences. But, she argues, quoting some of the researchers she consulted, continuing to explore these possibilities is vital in the face of the overwhelming evidence that our climate is changing for the worse. Occasional proofreading slips don't dampen the importance of this compact overview, a good starting place for teen readers and researchers on a critical issue. (source notes, glossary, selected bibliography, further information, index) (Nonfiction. 13-18)

Gr 9 Up-wanson explains the impacts of climate change, particularly the warming caused by carbon dioxide in the atmosphere. The author discusses how increased greenhouse gases contribute to powerful storms, extreme droughts, record temperatures, and melting ice sheets. Although replacing fossil fuels with renewables can help, some climatologists and engineers think more decisive action may be required. They are developing technologies that could alter Earth's existing systems to reduce atmospheric carbon dioxide. Swanson explains theories behind and potential implementation of strategies such as reforestation, carbon capture and sequestration, ocean fertilization, and solar radiation management. The pros and cons related to each are presented along with discussions on current controversies and difficulties related to the implementation of such technologies. Diagrams help explain concepts such as the biological and industrial carbon cycle and the geological carbon cycle, but the dense text and unfamiliar concepts require patient, committed reading. VERDICT Researchers will appreciate this sobering, weighty overview of an important and controversial topic.Kathy Piehl, Minnesota State University Library, Mankato