Sky News: Barack Obama is set to come under pressure to commit to a climate change summit as campaigners prepare to bombard the internet. It is not yet known whether the US President will attend the Copenhagen event They hope a "Twitterstorm" will raise awareness of the Copenhagen talks and force the US President to publicly respond. Despite speaking about the risks of global warming, it is not yet known whether Mr Obama will attend the UN-led summit in December. The new …