title: Google colab: Setting GCP project for BigQuery magic using an environment variable
body: <p>In colab, if I try to execute a simple bigquery query without explicitly providing the project-id like this:</p>
  
  <pre><code>%%bigquery
  SELECT 1 AS test
  </code></pre>
  
  <p>then I get the following error:</p>
  
  <pre><code>OSError: Project was not passed and could not be determined from the environment.
  </code></pre>
  
  <p>I realise I can mitigate this error by specifying the <code>--project</code> parameter in the <code>%%bq</code> magic:</p>
  
  <pre><code>%%bigquery --project my-project-id
  SELECT 1 AS test
  </code></pre>
  
  <p>but the text of this error suggest that perhaps it's possible to specify the project-id <strong>by setting an environment variable</strong> instead. Is this possible? </p>
  
  <p>I'd prefer to be able to set up the env var at the top of the notebook then not specify the project id each time. I tried a guess of <code>GCP_PROJECT</code> and googled around the issue but to no avail. I couldn't turn up any docs or answers as to which env var I can set for the projectid.</p>