The approximate value in US$ of the world cryptocurrency market capitalization is 1.04 trillion US$.
This calculation has been made multiplying the total amount of cryptocurrency by its value in dollars, keeping into consideration the different amounts of each cryptocurrency. In other words, we added the market capitalizations of all cryptocurrencies.
Here is a chart that shows the cryptocurrency market capitalization in the past 90 days.
Source of the chart
For further information, check out this page