cron script can't see files in Desktop

Question

It appears that my script, when run via cron, does not see the contents of my Desktop:

~/Code/scripts/problem.sh:

echo hello
cd ~/Desktop
echo $(pwd)
ls
echo hello2

Output when I run bash problem.sh from inside ~/Code/scripts:

hello
/Users/alfordsimon/Desktop
calendar.png
*more desktop files
hello2

crontab file:

* * * * * bash ~/Code/scripts/problem.sh >> ~/Code/scripts/problem.out

problem.out contents confirms that the script is running, but for some reason the Desktop files aren't showing:

hello
/Users/alfordsimon/Desktop
hello2

I haven't bothered trying to see if this issue is present for other directories. I'm trying to have a script automatically move my Screenshot files from Desktop to ~/Documents/screenshots every day (for testing purposes, the script currently runs every minute). What's going on? This is on my macbook—do I have to give my script permission to view Desktop files or something?