Modelling suggests that enough aerosols could have a substantive cooling effect.
Which is why it is so important now to have a substantive debate about both President Obama's vision of the federal government's role — and Paul Ryan's.
You could have a substantive argument on whether tax cuts for the rich stimulate the economy and benefit the middle class and the poor.
You could have a substantive argument on whether the government should play a role in providing health insurance to the uninsured, requiring coverage of pre-existing conditions.
If only the Bush administration were filled with serious conservatives, liberals thought, like back in the Reagan days, then we could at least have a substantive debate.
They require you to have a substantive amount in the kitty or they're going to be very leery about giving you a good bond rating".
… New Orleanians need to show the nation and one another that the city can have a substantive campaign and a fair election after Katrina.
This is politically astute, since eliminating the tax benefits that have a substantive budget impact would mean eliminating things voters love, like the mortgage-tax deduction.
"Political for the mayor means, 'I don't have a substantive answer to the allegations being made but I have to say something, so let me attack,' " he said.
"I'm being hopeful here, but maybe the climate has changed enough that you can have a substantive debate on the issue".
But I also worry that despite the exhilaration of recent weeks, when everything seemed to break their way in large part as a result of stupefying blunders by their adversaries, the Democrats still have a substantive job to do.
