Two years ago the Labor Party won a decisive election victory in part by riding a public mood demanding action on climate change after years of stonewalling.

The new Government promised to spearhead world efforts to reduce greenhouse gas emissions. Today it's on the run, retreating from a surge of militant anti-climate activism that believes climate science is a left-wing plot aimed at promoting elites, wrecking the economy and screwing the little man. What happened?

Part 1: Climate cyber-bullying

Australia's most distinguished climate scientists have become the target of a new form of cyber-bullying aimed at driving them out of the public debate.

In recent months, each time they enter the public debate through a newspaper article or radio interview these scientists are immediately subjected to a torrent of aggressive, abusive and, at times, threatening emails. Apart from the volume and viciousness of the emails, the campaign has two features - it is mostly anonymous and it appears to be orchestrated.

The messages are typically peppered with insults. One scientist was called a "Loudmouth, arrogant, conceited, ignorant wanker".

The emails frequently accuse the scientists of being frauds who manipulate their research in order to receive funding, such as this one to Ben McNeil at the UNSW:

"It's so obvious you are an activist going along with the climate change lie to protect your very lucrative employment contract."

They often blame the recipients of being guilty of crimes, as in this one received by Professor David Karoly at the University of Melbourne:

"It is probably not to (sic) extreme to suggest that your actions (deceitful) were so criminal to be compared with Hitler, Stalin and Pol Pot. It is called treason and genocide.

"Oh, as a scientist, you have destroyed peoples trust in my profession. You are a criminal . Lest we forget."

Receiving emails like these is unsettling and at times disturbing, which of course is the point. They become worrying when they cross the line to personal threats, such as these sent to Professor Andy Pitman at the UNSW:

"There will be a day of facing the music for the Pitman type frauds... Pitman you are a f**king fool!"

And this one:

"If we see you continue, we will get extremely organised and precise against you."

When Pitman politely replied to the last, the response was more aggressive:

"F**k off mate, stop the personal attacks. Just do your science or you will end up collateral damage in the war, GET IT."

All threats have to be taken seriously, and at times warrant calling in the police. The police are able to trace anonymous emails to their sources and take action against those who send them. The police are now advising those who received abusive and threatening emails to resist the immediate urge to delete them and keep them in a separate folder for future reference.

Climate campaigners have also noticed a surge in the frequency and virulence of this new form of cyber-bullying. The following was received by a young woman (who asked that her name not be used):

"Did you want to offer your children to be brutally gang-raped and then horribly tortured before being reminded of their parents socialist beliefs and actions?

"Burn in hell. Or in the main street, when the Australian public finally lynchs you."

Another campaigner opened her inbox to read this:

"F**k off!!!

"Or you will be chased down the street with burning stakes and hung from your f**king neck, until you are dead, dead, dead!

"F**k you little pieces of sh*t, show youselves in public!!!"

Greens Senator Christine Milne told me that senators' inboxes are bombarded every day by climate deniers and extremists, so that now they are running at least 10 to one against those who call for action on climate change.

She describes it as a "well-organised campaign of strident, offensive and insulting emails that go well beyond the bounds of the normal cut and thrust of politics".

It was widely reported that in the days before the Liberal Party leadership challenge last November, MPs were blitzed with emails from climate deniers. Some MPs were spooked into voting for Tony Abbott, the only one of the three contenders who had repudiated climate science. Australia's alternative government is now led by climate deniers.

Journalists hit

Journalists too have become the victims of cyber-bullying. I have spoken to several, off the record, who have told of torrents of abusive emails when they report on climate change, including some sufficiently threatening for them to consult their supervisors and consider police action.

One was particularly disturbed at references to his wife. Another received the following from someone who gave his name and identified himself as medical representative at major pharmaceutical's company:

"You sad sack of s**t. It's ok to trash climate change sceptics yet, when the shoe is on the other foot, you become a vindictive, nasty piece of s**t not able to face the fact that you're wrong about climate change and you're reputation is now trash."

Anonymous emails are usually more graphic.

"Your mother was a goat f**ker!!!!!! Your father was a turd!!!!!!! You will be one of the first taken out in the revolution!!!!!!!! Your head will be on a stake!! C**t!"

Few of those on the receiving end of this hatred doubt that the emails are being orchestrated. Scores of abusive emails over a few hours are unlikely to be the product of a large number of individuals spontaneously making the effort to track down an email address and pour forth their rage.

While some individuals act alone, increasingly the attacks are arranged by one or more denialist organisations. It's fair to assume operatives in these organisations constantly monitor the media and, when a story or interview they don't like appears, send messages out to lists of supporters, linking to the comments, providing the scientist's email address and urging them to let him or her know what they think.

One or two of the cyber-bullies have hinted at the level of organisation, with one following an abusive rant with the comment:"Copies of my e-mails to you are also being passed out to a huge network for future reference."

Net rage and free speech

The purpose of this new form of cyber-bullying seems clear; it is to upset and intimidate the targets, making them reluctant to participate further in the climate change debate or to change what they say. While the internet is often held up as the instrument of free speech, it is often used for the opposite purpose, to drive people out of the public debate.

Unlike the letters pages of newspapers, on the internet anonymity is accepted and the gate-keepers, where they exist, are more lax, so the normal constraints on social discourse do not apply. On the internet, the demons of the human psyche find a play-ground.

If a group attempts to have a considered discussion about climate science on an open forum it is very soon deluged with enraged attacks on climate science, sometimes linking for authority to well-known denialist websites. Most scientists long ago stopped attempting to correct the mish-mash of absurd misrepresentations and lies in web "discussions".

Is the new campaign of cyber-bullying working? Receiving a large number of offensive emails certainly wears most people down. Some scientists and journalists probably do change what they say or withdraw from debate. Others have strategies for dealing with the abuse-never replying, deleting without reading or swapping loony emails with colleagues, and cultivating a thick skin.

The effect of the cyber-bullying campaign on some scientists-including those I have mentioned-is quite opposite to the intended one. The attempts at intimidation have only made them more resolved to keep talking to the public about their research. Their courage under fire stands in contrast to the cowardice of the anonymous emailers.

Tomorrow: Who is behind the cyber-bullying campaign?