Carbon offsetting

Carbon offsetting is the practice of compensating for the release of carbon dioxide arising from human activity by participating or investing in schemes that make equivalent reductions in carbon emissions. Writing for the Bulletin of the Atomic Scientists, Fiona Harvey provides an overview of the pros and cons of carbon offsetting.  

Carbon offsetting is possible because carbon dioxide has the same impact on the planet regardless of where it is emitted. This means, as Harvey explains, that “if a ton of carbon dioxide can be absorbed from the atmosphere in one part of the world it should cancel out a ton of the gas emitted in another.” Projects that reduce or store carbon include tree planting, forest preservation, wind farms and solar power. Carbon credits are often awarded to companies that invest in offsetting schemes.  

While carbon offsetting schemes have been welcomed by many, Harvey warns against using them as an excuse to put off more systemic reforms. Deforestation, which experts estimate is currently taking place at a rate equivalent to 27 football pitches being removed per minute, means that merely planting trees cannot make up for the carbon lost when forests are cleared. Schemes such as Reducing Emissions from Deforestation and Degradation (known as REDD+), which award carbon credits to forest owners who avoid deforestation, are considered by some to be flawed. Harvey states that problems include:  

  • areas of forest not allocated for carbon offsetting can still be cut down;  
  • examples of loggers targeting high value trees while leaving the rest of the forest; and 
  • governments failing to enforce protection, leading to frequent violations in protected forest.  

For these reasons, the “gold standard” carbon offsetting program (backed by groups including the World Wildlife Foundation) does not endorse the issuing of carbon credits for avoided deforestation. Despite this, Harvey says that in the “absence of a global system that rewards forested nations for preserving their forest […] offsetting does provide a source of income and protection to some areas, and at least some form of monitoring and accountability to ensure that companies are sticking to their commitments”.

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A new Alzheimer’s drug

On 7 June 2021, aducanumab became the first new Alzheimer’s disease drug approved by the US Food and Drug Administration (FDA) since 2003. The drug, marketed as Aduhelm, has been shown to clear a toxic protein known as amyloid, which accumulates in the brains of people with Alzheimer’s and is thought to cause damage.  

While some have welcomed the approval, others have warned that the evidence of the drug’s efficacy is limited. Writing for the journal Science, Kelly Servick explains the current debate around aducanumab.  

Some criticism has focused on uncertain results from clinical trials. Biogen, the pharmaceutical company behind the drug, along with its Japanese partner Eisai, halted trials in 2019 after an interim analysis of the data suggested that the drug provided no benefit to patients. However, later that year the two companies announced a reversal in policy, and published a new analysis showing a 22% reduction in cognitive decline associated with the drug. This reversal, Servick says, left many experts “confused and sceptical”.  

The FDA has also faced criticism for using an accelerated approval process for the drug. Servick quotes one expert who says that the “switch at the last minute from a standard approval process to an accelerated pathway that doesn’t require clinical improvements” is unprecedented. The FDA have stated that Biogen will be required to complete a post-approval clinical trial to verify the drug’s benefit.  

David Thomas, Head of Policy at Alzheimer’s Research UK, welcomed the development, whilst also cautioning that the drug still had hurdles to overcome before it reached the UK. Regulators in the UK and the EU are currently completing their own analysis of the data around aducanumab and are expected to announce their findings in the autumn of 2021.  

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