An Israeli ground invasion of the Gazan city of Rafah would push starvation-related deaths over a tipping point in the strip’s south, a humanitarian group has warned. Israeli forces seized southern Gaza’s Rafah border crossing with Egypt on Tuesday as they began a long-threatened attack against the overcrowded area sheltering more than a million people. Refugees International president Jeremy Konyndyk said on Wednesday that the definition of famine requires a highly elevated rate of death as a result of starvation and disease. “We’ve passed a concerning tipping point on that… in the north, and…