In his new year message, Justin Welby said attacks in London and Manchester, and the Grenfell Tower fire, were met with heroism from the emergency teams.
He also used his message to ask whether the darkness or light of human kindness would define the year ahead.
He was speaking from London Ambulance Service headquarters in Waterloo.
The Anglican leader recalled the desperation and sorrow he felt when he visited Grenfell Tower in west London as it burned.
He also highlighted the plight of people who were "struggling to find work or relying on food banks" and those who were bereaved, or coping with poor mental health or physical illness.
"When things feel unrelentingly difficult, there are often questions which hang in the air: Is there any light at all? Does anyone care?" he said.
Noses back to the grindstone...seemingly interminably wet commutes of 2018 have begun...
How do you feel about returning to work? Excited? Sad? Anxious? Anti-climatic? How do the people you work with feel? Is anyone suffering? It's a strong word. The harassment revelations of 2017 taught us that we need to care more about it. People may be suffering silently alongside you.
A daily act of compassion or kindness could make a big difference. I reckon it's worth adding to the list of New Years resolutions. I've given up on the low carb diet already. This one feels more important.