As of 2018, the leading U.S. telecom companies (based on market cap*), AT&T and Verizon, were emitting 16.9 and 11.2 million metric tons of CO2 equivalent (MtCO2e), respectively. However, both companies are committed to going carbon neutral by 2035 in their direct and indirect emissions, making significant steps to reduce their carbon footprint.
Energy consumption
In order to lessen their carbon dioxide (CO2) emissions, AT&T and Verizon will have to continuously reduce energy consumption of their telecommunications networks. This reduction specifically in the networks is crucial for reducing the companies’ carbon footprint. In 2018, the United States recorded its highest annual
fossil fuel consumption levels to date, as energy demand is largely covered by fossil fuels. Verizon revealed in its 2019 Environmental, Social, and Governance Report, that 91 percent of its 2018 greenhouse gas emissions (GHG) profile comes from the electricity generation used to power their telecom networks. Therefore, in order to decrease the consumption in electricity, Verizon is employing new cooling systems that will put less strain on the networks, allowing for increased energy efficiency.
Preventing greenhouse gas emissions
From 2018 to 2019 the United States saw a 
1.7 percent decrease in greenhouse gas emissions. A
broad spectrum of strategies  exists to mitigate these CO2 emissions and promote overall sustainable objectives. Carbon neutrality can be achieved by balancing CO2 emissions with removal (also known as carbon offsetting) or through eliminating CO2 emissions altogether. AT&T and Verizon are dedicating themselves to carbon neutrality by 2035 through a combination of the methods above. Many of the other leading technology firms, including Apple, Alphabet, Microsoft, Facebook, and Salesforce, have also dedicated themselves to zero-sum emissions in the future.