History is being made this week in a packed Seattle-area courtroom as five activists standing trial for blocking an oil train argue that they were compelled to act because of the threat of climate change.The trial marks the first time a U.S. judge has permitted the \u0022necessity defense\u0022 to be used in a case relating to climate action.\u0022Their direct action, their civil disobedience was a necessary act to prevent the greater harm of climate change,\u0022 activist Tim DeChristopher of the Climate Disobedience Center told local news KIRO7 on Monday. \u0022In this case, the greater harm of the risk of oil explosions as the trains go through local communities.\u0022During opening proceedings on Monday, defendant Patrick Mazza, who is representing himself, told the courtroom that he and his co-defendants will \u0022present evidence about the oil train threat,\u0022 arguing that the impact of so-called \u0022bomb trains\u0022 and the subsequent carbon emissions are so serious that the group\u0026#039;s actions were necessary to avert them.In September 2014, the defendants, known as the Delta 5, staged an 8-hour blockade of a BNSF rail line carrying crude oil through the town of Everett. The group tied themselves to a 25-foot tripod structure which they had erected over the tracks. Mazza, along with Abby Brockway, Mike Lapointe, Jackie Minchew, and Liz Spoerri have been charged with \u0022criminal trespass.\u0022\u0022I believe what they did was justified. I believe if things keep going the way they’re going, we’re heading toward climate disaster,\u0022 said Diane Cortese, who was among the 100 or so supporters who gathered in front of the South Snohomish County District Court in Lynnwood, Washington. \u0022In order to see change, we’re all going to need more civil disobedience,\u0022 she said.The trial has garnered national attention. Environmentalists fed up with the continued and dangerous expansion of fossil fuels hope the climate necessity defense will prove to be a valuable legal tool as the need for direct action grows.DeChristopher, who had attempted to use the defense to justify his 2011 disruption of a federal gas lease auction in Utah, explained on Democracy Now! Monday what the potential implications are for this trial.\u0022This is the first time that defendants who have taken civil disobedience action will be able to present a full defense, including climate scientists and oil train explosion experts,\u0022 he said, \u0022as well as sharing all their own testimony about why they were driven to take this action, why the government\u0026#039;s response to climate change is not adequate, why citizens are called to take action in this way on their own - and have six random jurors, that are not climate activists, that are just regular people who are selected for jury duty, make their own decision of whether or not this kind of action is justified.\u0022And to me,\u0022 DeChristopher continued, \u0022that involvement of the jury is really critical, because a fully informed and empowered jury is the, really, only difference between actual justice and mere legalism.\u0022As activist resource Climate Disobedience Center notes, with Congress\u0026#039;s recent decision to lift the oil export ban, there will be an even-greater push for more oil-by-rail and other export facilities. \u0022Activists have pledged an increased campaign of direct action and civil disobedience until these terminals are rejected,\u0022 the group states. \u0022The outcome of next week’s trial could set important precedent for future actions of this kind.\u0022Explaining why she was moved to direct action, Spoerri said, \u0022It was clear that the political reality is not keeping up with the physical reality, and that citizens need to lead.\u0022She continued: \u0022We have solutions but we are not acting fast enough. We don’t have to build terminals and then turn a blind eye to the consequences...If we reorient ourselves to prevent climate chaos we can address so many other problems at the same time.\u0022DeChristopher is reporting on the trial live on Twitter as arguments continue this week while others are sharing news about the case under the hashtag #Delta5. Supporters have also set up a legal fund for the group.