a team from the pasta institute for climate impact research or pic thinks this could save the ice sheet and stop coastal cities such as shanghai and new york from becoming submerged if and arctic as giant ice sheet melts pick researchers estimate that sea levels would rise by more than 3 meters. it's always a picture doing what scientists do best the dokken experiment and that's what we call it in german. so that's all just hypothetical a thought experiment just like most of the ideas on how to intervene in the earth's climate system it's called geo engineering and there are 2 main approaches. first extract carbon dioxide from the atmosphere known as carbon dioxide removal and 2nd reflect solar energy to prevent further heating called solar radiation management let's start with number one. a whole range of measures are being discussed on the one hand things like reforestation. trees absorb c o 2 from the atmosphere as they live and grow and when for 3rd preserved they can act as a carbon sink. and then there's the high tech version of that technology that would suck the o 2 out of the a

for climate and economics at the world resources institute — a global environmental research organisation. thank you forjoining us. good to have been with us. could you tell me what you think the impactlevel we have the states and cities, business and investors, universities, who have all woken up to the challenge of climate change and the opportunities of taking action so we now have something like 70% of us gdp and 65% of the population in those states, cities and businesses moving forward. in total bet amounts to basically the second largest economy in the world, second largest economy in the world, second only to the usa and larger than china. so while we have a worrying and concerning signal at federal level we also have a lot of action and momentum building at the sad national level. so a mixed picture, not all one way but there isa picture, not all one way but there is a leadership issue, certainly in terms of global leadership and the contribution made to global debate on climate change and credibility of that debate and that surely is in the eyes of many people immensely damaging. absolutely, we didn't see action at sub—national level and that amounts to a lot but at the sam