Modeling and Forecasting the Evolutionary Economic Development of the BRICS and G7 Countries in the First Half of the Twenty-First Century

he work describes the process of formation of the inter-civilizational association BRICS and its transition to a new stage of development in connection with the expansion to BRICS 11 at the 15th summit in Johannesburg (South Africa, August 2023). The association is expected to expand further by admitting a second wave of states that are waiting for their turn. BRICS+ is now becoming the basis of a new, successfully emerging, equitable multipolar world order, which is becoming a real alternative to the short-lived unipolar world order with the US hegemony, supported by the G7 countries. Today, the BRICS association has already reached parity with the G7. But in the future, the balance of power will increasingly shift in favor of BRICS+. It is shown that BRICS+ will have sufficient technological sovereignty, a dominant supply of natural resources and financial institutions to allow a sustainable association to develop successfully in a world currently divided on a bloc basis. For the purpose of long-term modeling and forecasting of the economic development of the vanguard countries that are members of the BRICS+ and G7 associations, new models that adequately describe demographic dynamics and total factor productivity (TFP) have been selected, adapted, and partially developed. It is shown that a production function (PF) consisting of the above-mentioned two factors – demography and TFP – is sufficient for forecasting long-term economic growth. All models are verified using actual data on these factors for the period fr om 1950 to 2020 and show high approximation accuracy. The proposed models were used to calculate the projected trajectories of demographic dynamics, technological progress and economic growth of the BRICS+ and G7 vanguard countries. Their comparative analysis has been carried out, showing that in the context of the current geo-economic fragmentation of the world, the BRICS+ countries are able to develop autonomously and sustainably at a rapid pace and become the locomotive of world development, ensuring the sustainable development of the countries of the Global South. It is shown that by the middle of the twenty-first century, the share of the BRICS+ countries in the world economy is expected to reach 80 % and they will be home to about 2/3 of the world's population.