a heat dome which traps warm air remains parked over regions of north america and is believed to be intensifying. phoenix, arizona is expected to break its record of more than 18 consecutive days with temperatures above 43 degrees celsius, or 109 degrees fahrenheit. and it s notjust the us. parts of europe are expected to see record temperatures in the coming days, with reports of tourists collapsing in the heat in italy. the beginning ofjuly was the hottest week on record for the planet. 0ur climate editor justin rowlatt has been looking into the earth s long term trends when it comes to rising temperatures. this shows estimated average global temperatures over the last 800,000 years. look at how the world went in and out of ice ages. let s add in carbon dioxide levels and look how closely they track the temperature and just look at how carbon dioxide spikes here at the end of the graph. now, let s zoom in to the last
just look at the mayhem caused by torrential rain in india. last week was the hottest week ever recorded. climate scientists say the heat and the rain is driven in part by global warming. this shows estimated average global temperatures over the last 800,000 years. look how the world went in and out of ice ages. now, let s add in carbon dioxide levels and look how closely they track the temperature, and just look how carbon dioxide spikes here at the end of the graph. now, let s zoom in to the last 12,000 years. look how the world gradually warms, then temperatures level out, becoming much more stable than during the ice age. we human beings, we have been around for about 300,000 years, but it s only in this period of warm and stable temperatures that we learnt to grow crops
this shows estimated average global temperatures over the last 800,000 years. look how the world went in and out of ice ages. now, let s add in carbon dioxide levels and look how closely they track the temperature, and just look how carbon dioxide spikes here at the end of the graph. now, let s zoom in to the last 12,000 years. look how the world gradually warms, then temperatures level out, becoming much more stable than during the ice age. we human beings, we have been around for about 300,000 years, but it s only in this period of warm and stable temperatures that we learnt to grow crops and civilisation developed. now let s look at the last 2,000 years. temperatures remain stable until just over there at the end of the graph. the steam engine was invented, the industrial revolution took off, man made carbon dioxide emissions started to increase and just look what happened
the point of no return. you make the argument that we are not. yeah, this is a common misunderstanding. we scientists have to take responsibility for it. for years, we communicated the idea that the planet would continue to warm up even after we stopped putting carbon pollution into the atmosphere. it s related to the sluggishness of the oceans that continue to warm up. our models, the climate models that we were using in those experiments were nearly as comprehensive as they have become over the past decade. we understand that well while we have that effect, the laggan sluggishness of the oceans, the oceans are doing something else. they are constantly pulling carbon dioxide out of the atmosphere. if we stop polluting, those co2 levels, those carbon dioxide levels start to come down. we lower the greenhouse effect. all of that averages out fortuitously in a way that says that as soon as we stop
they are using. we only have an approximate guess of how long the us could the oxygen reserves are. if the banging is caused by the submersible, they are obviously still conscious. it is the oxygen levels drop, the carbon dioxide levels go up and temperature goes down, at some point they will lose consciousness. but if the buying is them, then at least one occupant has to be conscious. one occupant has to be conscious. ., , ., , ., conscious. can you give us an idea, conscious. can you give us an idea. once conscious. can you give us an idea, once they conscious. can you give us an idea, once they should - conscious. can you give us an idea, once they should the i conscious. can you give us an| idea, once they should the gin runs out, bashment once the oxygen runs out, how much longer would they remain alive? again that is really a function of their temperature. it s not the oxygen just running out, of their temperature. it s not the oxygenjust running out, it will not go down