We all know that seeking shade is one of the best ways to escape the heat. But could a giant \u2018sun umbrella\u2019 help block harmful UV rays and cool the Earth?<\/p>\n
That\u2019s the latest idea from a US astronomer at the University of Hawai\u02bbi.<\/p>\n
This isn\u2019t the first time space-based sun shields – mirrors or shades placed in orbit between the sun and Earth – have been proposed for climate change prevention.<\/p>\n
Until now, however, scientists have struggled to design a shield that balances weight and costs.<\/p>\n
A potential solution is to tether it to a counterweight filled with asteroid material, according to the new proposal published in the Proceedings of the National Academy of Sciences<\/a> (PNAS) journal.<\/p>\n If the design is workable, it could start mitigating climate change within decades, the paper\u2019s author Istv\u00e1n Szapudi claims.<\/p>\n How could solar shields stop climate change? Until now, the\u00a0solar<\/strong><\/a>\u00a0shield concept faced a major hurdle: weight.<\/p>\n Previous proposals have placed the shield at the point where the Earth\u2019s gravity and the sun\u2019s radiation pressure are in balance.<\/p>\n However, these two counteracting forces mean the shield would have to meet minimum weight requirements to ensure it stays in place. This rules out low-cost, lightweight materials like graphene, which could be easily lifted into\u00a0space<\/strong><\/a>.<\/p>\n By attaching the shield to a counterweight, positioned towards the sun, these weight restrictions could be circumvented, Szapudi theorises.<\/p>\n The shield could also be placed closer to Earth, making it more effective.<\/p>\n How would a tethered solar shield work? The counterweight would slowly open once in\u00a0space<\/strong><\/a>, allowing it to gradually fill with lunar dust or asteroid material that would act as ballast.<\/p>\n As the ballast would be captured in space, it would not need to be launched from Earth.<\/p>\n Acting as a counterweight, it would dramatically reduce the weight of the shield, according to Szapudi.<\/p>\n Together, the shield and\u00a0counterweight<\/strong><\/a>\u00a0would weigh around 318 million metric tonnes – 100 times less than untethered designs.<\/p>\n The shield itself, which is the part that would need to be launched into Space, would only account for around 32,000 metric tonnes, or one per cent of the weight.<\/p>\n Rockets today are capable of lifting up to 45,000 metric tonnes into low Earth orbit.<\/p>\n Why are some scientists against solar radiation modification? Acknowledging the potential risks of modifying the Earth\u2019s atmosphere, Szapudi says space-based strategies are preferable.<\/p>\n \u201cGiven the severity of the problem, any avenue that might lead to the partial mitigation<\/a> of a catastrophe should be investigated,\u201d he writes.<\/p>\n Yet not all scientists are in agreement.<\/p>\n In a 2008 paper titled \u201820 reasons why geoengineering may be a bad idea\u2019, US climatologist Alan Robock compares these technologies to putting Earth on \u201clife support\u201d, saying \u201cthe cure may be worse than the disease\u201d.<\/p>\n Robock warns of the unknown consequences of such technologies, including the effects on regional climate<\/a>, plants and solar power.<\/p>\n He also notes that relying on SRM technologies could result in abandoning\u00a0carbon emissions<\/strong><\/a>\u00a0cuts. This would allow other damaging effects of greenhouse gases, such as ocean<\/a> acidification, to continue.<\/p>\n To account for the unpredictability of geoengineering, Szapudi suggests \u201ca modular and reversible approach\u201d using several smaller shields over a single shield.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":" We might one step closer to a giant solar shade that could help cool the Earth. We all know that seeking shade is one of the best ways to escape the heat. But could a giant \u2018sun umbrella\u2019 help block harmful UV rays and cool the Earth? That\u2019s the latest idea from a US astronomer […]<\/p>\n","protected":false},"author":2,"featured_media":7840,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-7839","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/posts\/7839","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/comments?post=7839"}],"version-history":[{"count":4,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/posts\/7839\/revisions"}],"predecessor-version":[{"id":7844,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/posts\/7839\/revisions\/7844"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/media\/7840"}],"wp:attachment":[{"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/media?parent=7839"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/categories?post=7839"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cfwt.sua.ac.tz\/ecosystems\/wp-json\/wp\/v2\/tags?post=7839"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n<\/strong>‘Sun blocking’ technologies – also known as ‘solar radiation modification’ (SRM) – could theoretically cool down the Earth by shading it from some of the sun\u2019s rays.<\/p>\n
\n<\/strong>The solar shield would be attached to a counterweight by a strong graphene tether.<\/p>\n
\n<\/strong>The field of solar radiation modification includes other technologies such as solar radiation and pumping\u00a0sun-blocking particles<\/strong><\/a>\u00a0into the Earth\u2019s atmosphere.<\/p>\n