Campaigners have highlighted the effects of climate change during a rally in Edinburgh.
Green MSP Mark Ballard was among campaigners at the rally
Organisers of the event also sought to champion proposed congestion charging plans for the city during the event.
However, anti-tolls campaigners said the congestion charging would only lead to an increase in pollution.
Green MSP Mark Ballard said Scotland could play a leading role in promoting a prosperous and environmentally friendly economy.
Campaigners in Edinburgh and London were seeking to highlight the Kyoto protocol - the international agreement on emissions - which comes into force on Wednesday.
Dozens of Edinburgh campaigners assembled at the Scottish Parliament where Mr Ballard addressed them.
He said: "As host of the G8 summit, and with the UK taking presidency of the EU, we are in prime position to show how a prosperous economy can be married with a thriving environment and high quality of life.
"Today, we are urging executive ministers and business leaders to exploit this opportunity.
"Setting a Scottish target for reducing climate change gases and accelerating the introduction of renewable energy would show that Scotland really can punch above its weight and set an inspiring example to other small countries."
Dr Dan Barlow, of Friends of the Earth, said: "The Kyoto Protocol coming into force will be only the first step forward and we urgently need the UK and other industrialised countries to make rapid progress on agreeing greater emissions cuts."
'Reduction in emissions'
The day's event was organised by campaign group pro congestion charging body Get Edinburgh Moving.
Spokesman Luke Reade said: "We need the congestion charge if Edinburgh is to make its contribution to reducing climate change.
"The scheme would cut city centre climate emissions by 10% from the first day, a total of 4000 tonnes of carbon dioxide in total.
"The London scheme had a better than anticipated impact on greenhouse gas reduction, with a 19% reduction in emissions.
"Everyone is very keen to say that we need to tackle climate change but now we need to see action taken."
However, a spokesperson for the National Alliance Against Tolls said Edinburgh's residents would not be duped by the carnival.
He said: "There is unlikely to be any reduction in greenhouse gases as cars make longer journeys to avoid the tolls."