one of them for this is professor tom crowther from the swiss federal institute of technology in zurich welcome to day w didn't we already know that trees absorb carbon dioxide and there are lots of tree planting schemes already out there to offset environmental damage. yes you're exactly right we've known that trees are an amazing carbon trap from the last well over the last century and there are projects out there trying to promote restoration but what this new study shows is actually we've got the 1st quantitative understanding of how much that can achieve and it's actually 10 times more than we previously expected placing restoration far far higher than the next best climate change solution so it's really about figuring out the best ways to allocate our resources and now we know that restoration is a powerful way a trillion trees sounds like an awful lot how much space is that going to take why would they go. so that's what we've modeled as way trees can exist on the planet and when you subtract away existing urban land and agricultural land we're left with the world's degraded land

white house correspondent philip crowther t thank you s so much. now we e want to give you a lite more conontext to the story the strait o of hormuz shows is the world's most important oil artery and has been at the heart of recent tensionss between washington and tehran. at its narrowest point ships waters but thehe us says these e international waters. it's one of the most important oil shipping routes in the worl. the strait of hormuz. the narrow waterway of just fifty five kilometers between iran and mine is a crucial trade artery for middle east oil producers. more than seventeen million barrels of crude passed through the strait perer day in. twenty seventeen accounting for nearly 20% of globalal oil consumptionn according to oil ananalytics fifirm for tax at te maritime cororridor lies in the territorial waters of both you ron and mon. but iran's revolutionary guard considers itself the gate keepe. deploys ships to patrol the wawater way and r regularly cons naval l exercises there. ththe straits economicc importae has made it aa hot spot fo

and that's what we're doing and that's what we're working on so far that's a stretch for the crowther are a man in washington for that good evening to you we've heard trump speaking a little bit that. tells a bit more about what he's been saying. well his messageges -- not necearary that thehe united stas is l leading the world when it comes to environmental issues but that's the united states is- first of all giving priority to economic growth and the that van will l lead to a clean -- environment in the united state- i think your introduction was just right the statistics on the facts speak for themselves this is the kind of event that needs a lock a lot of fact checking because of course. thee united states is not leadig when it comes to the environment is certainly is not leading when it comes to fighting climate change as you said the most important. policy reversal -- from this administration was of course that exit the announced exit -- by the uniteted states from the paris climate agreement essentially that is the message from this president's that's nothing will get in the wa

joining me is planetary scientist sarah crowther from the university of manchester.ose missions. so what do these tell us? they are all different colours, shapes and textures. they are, so if you look up textures. they are, so if you look up at the moon in the sky at night, some areas are dark in some areas are quite light. we have different types of rock from the different areas. so this type of rock comes from the lighter areas of the moon, thatis from the lighter areas of the moon, that is effectively the crust of the moon, and darker assault rocks were formed by ancient volcanoes on the moon ‘— formed by ancient volcanoes on the moon —— basalt. formed by ancient volcanoes on the moon -- basalt. so like us, the moon has a call. it does, it is much smaller than ours, but it does. we are here all weekend, we will have these rocks on display, so people can come and look at them, hold the moon. hopefully the weather will improve for you. it is a little bit wet at the moment but we are doing our best to stay dry here atjodrell bank. you will be hard pressed to stay com