A district court judge in North Dakota has barred climate change scientist Dr. James Hansen and other experts from testifying in the landmark trial of Michael Foster, one of the 11 climate activists with the group Climate Direct Action who temporarily halted the flow of tar sands bitumen from Canada into the U.S. in a #ShutItDown action last October.\u0022The science has been made clear to the government, but the government isn\u0026#039;t doing its job.\u0022—Dr. James HansenWorking simultaneously in North Dakota, Minnesota, Montana, and Washington, five of the activists \u0022entered fenced-off areas and closed the emergency valves\u0022 for five pipelines—operated by Enbridge, Spectra Energy, Kinder Morgan, and TransCanada—as Foster, a Seatte-based mental health counselor in his 50s, described in a Newsweek column published Tuesday. The five activists have been nicknamed \u0022valve turners.\u0022\u0022I shut off the valve on TransCanada\u0026#039;s Keystone 1 pipeline in North Dakota. We called the pipeline companies in advance to notify them, livestreamed our action to prove it wasn\u0026#039;t a hoax, then peacefully waited for arrest,\u0022 he wrote. Foster, whose trial started Monday, has been charged with two Class B felonies and two misdemeanors, and faces up to 22 years in jail. He has pleaded \u0022not guilty,\u0022 and his team is asking to present what is called a necessity defense.As Jeremy Brecher explained in a Common Dreams op-ed in March: \u0022To make a necessity defense, the accused must prove that they believed their act was necessary to avoid or minimize a harm; that the harm was greater than the harm resulting from the violation of the law; and that there were no reasonable legal alternatives.\u0022 To achieve that, the defense \u0022will have to prove to the court that the harm of climate change is greater than that of shutting a pipeline,\u0022 which they planned to do by calling \u0022expert witnesses who will have no difficulty laying out the catastrophic current and future effects of fossil fuel emissions.\u0022However, they hit a roadblock on Wednesday, when the judge barred Hansen—a former NASA scientist who has been called \u0022the father of modern climate change awareness\u0022—and other key climate witnesses from testifying. The judge, according to Foster\u0026#039;s representatives, claimed \u0022presentation of climate change testimony and evidence would confuse the jury and mislead them.\u0022\u0022The refusal to allow me to testify is likely to have a huge impact on the jurors\u0026#039; decisions,\u0022 Hansen told\u0026nbsp;Common Dreams. \u0022If they understood what he was trying to prevent, the morality of what he was doing, the immorality of our governments as they get paid off by the fossil fuel industry, I think that he would have been found innocent. As it is now, I\u0026#039;m afraid that he can look forward to cooking in the slammer for some time.\u0022\u0022If this court refuses to take into consideration why he did what he did, and the fact that he had previously tried every lawful action that our democracy allows, it will suggest that our judicial system has descended to a point that it is incapable of being fair,\u0022 he said. \u0022It is giving priority to the rights of big business over the public, and over young people in particular. Governments were instituted to protect people, not corporations.\u0022Before arriving in North Dakota, Hansen prepared a written expert report outlining how North Dakotans and all Americans are in danger from climate change unless \u0022meaningful action to confront the crisis\u0022 is taken. The report, he said, \u0022emphasizes the fundamental concepts of climate change,\u0022 and \u0022that the slow response of the climate system implies that young people and future generations will experience far greater effects from our CO2 emissions than we do.\u0022\u0022It is this aspect, that makes it a case of inter-generational injustice if we continue our high emissions,\u0022 Hansen continued. \u0022The tar sands oil, and other unconventional fossil fuels, specifically fracking to get more oil and gas, if we allow these to be exploited, will push the system beyond the point of no return, assuring that future generations experience many-meter sea level rise and loss of our coastal cities.\u0022\u0022The U.S. is among the nations that has the most to lose,\u0022 he added. \u0022Of course we are the largest contributor to the excess CO2 in the air, so it might be argued there is some justice in that.\u0026nbsp; However, the tragedy is that we could be the solution and would benefit greatly from it.\u0022Hansen and Foster gave a press conference from North Dakota on Thursday afternoon.\u0022I am in the middle of being tried in front of a jury of 12 people, who will not, it turns out, be hearing from some wonderful expert witnesses,\u0022 lamented Foster at the press conference. He said that Hansen and others were \u0022ready to testify to different elements of the reasons why I had to do what I did—why it was necessary and an emergency for me to shut down the Keystone 1 pipeline.\u0022\u0026nbsp;Asked to share what he would have said on the stand, Hansen said: \u0022The basic thing is, we have a crisis, which is hard for the public to recognize, but that\u0026#039;s why we have governments—and we have a National Academy of Sciences. The science has been made clear to the government, but the government isn\u0026#039;t doing its job, so people like you are trying to draw attention to the idiocy that we have in Washington.\u0022Watch (start at 1:45):\u0022America\u0026#039;s courts are an essential place to discuss the imperative for citizens act to against climate change,\u0022 Foster wrote in Newsweek. \u0022As a matter of justice, it\u0026#039;s fundamental to have that discussion, and cite evidence to support it, in front of a jury. The prosecution disagrees.\u0022\u0022It moved to block me from presenting evidence of climate danger, the main reason I acted,\u0022 he continued. \u0022Prosecutors argue jurors might be biased by hearing about climate change, or being shown evidence of how dirty fossil fuels like tar sands affect it, and what those impacts mean for North Dakotans and all of us.\u0022Foster is the second of the the valve turners to stand trial. \u0022The first activist to stand trial, Ken Ward, was convicted of burglary in Washington in June,\u0022 the Associated Press reports. \u0022Jurors deadlocked on a sabotage count. Ward was sentenced to the two days he had already spent behind bars, plus community supervision and community service.\u0022Prosecutors have dropped charges against Lindsey Grayzel and Carl Davis, who filmed Ward\u0026#039;s protest. However, Samuel Jessup, who filmed Foster\u0026#039;s protest, is also standing trial in North Dakota this week, and criminal cases are pending against Ben Joldersma, Emily Johnston, Annette Klapstein, and Steve Liptay, in Minnesota, as well as Leonard Higgins and Reed Ingalls in Montana.This post has been updated to include statements from Dr. James Hansen.