According to the EPA (Environmental Protection Agency)
- As of 2020,
* Electricity makes up for 25% of greenhouse gases
* Transportation is 27%
By cutting down on these, we would be dealing with approximately 50% of the greenhouse gas emissions.

For electricity, we burn energy through things such as heating, ventilation, appliances, air conditioning and lighting. By switching away from fossil fuels and moving to cleaner energies, we would significantly cut down on fossil fuel emissions.

For transportation, a way that we could cut down on emitting fossil fuels is through electric cars and other public transportation vehicles. Using gas through regular means is through burning coal. Coal emits lots of CO2 (54% out of all of the total CO2 emissions to be exact). Another idea is to encourage the use of electric cars and creating more charging ports scattered throughout the city.
Using energies such as solar, hydroelectric, nuclear, and wind are all non emitting, so all of those would be an option for cutting down on emissions.

Author n/a, Updated April 14th, 2022, "Sources of Greenhouse Gas Emissions" Environmental Protection Agency (EPA), https://www.epa.gov/ghgemissions/source … equivalent.

I agree with you if we get rid of these two aspect of the greenhouse gas emissions in a country which like you said it would be about 50% less greenhouse gas half of our problem is solved right there. We can then later try and solve for the other 50 percent.

I really agree with your idea to reduce the greenhouse gas emissions by generating electricity not using fossil fuel.
And talking about the CO2 emissions in transportation, I also agree with the idea using electric cars. I also think that we can design some airplanes that use hydrogen as fuel instead of oil. Burning hydrogen will produce water vapor as waste and does not heat up the atmosphere.