Ethereum's foundational vision is to become a "world computer." To realize this ambitious goal, its developers laid out a structured upgrade path from the very beginning. This journey is divided into four distinct phases: Frontier, Homestead, Metropolis, and Serenity.
The network is currently in its third phase. The first three stages constitute what is often referred to as Ethereum 1.0. The final phase, Serenity, is widely known as Ethereum 2.0. It's important to note that the core Ethereum team has moved away from the "Ethereum 2.0" terminology to avoid confusion, but this article will use the term for clarity and familiarity.
The primary purpose of these major upgrades is to address critical limitations that have emerged as the network has grown. These challenges are significant and multifaceted.
Key Challenges Driving Ethereum's Upgrade
- High Energy Consumption: Ethereum currently relies on a Proof-of-Work (PoW) consensus mechanism. This requires miners to use powerful, energy-intensive computing hardware to solve complex mathematical problems and validate transactions. This process consumes a massive amount of electricity, leading to widespread criticism regarding its environmental impact.
- Network Performance and Scalability: The Ethereum network processes transactions relatively slowly. With a block time of approximately 12-15 seconds and a transaction throughput (TPS) of around 15, the network often becomes congested. This congestion limits its ability to support large-scale commercial applications and hinders overall growth.
- High Transaction Fees (Gas Fees): To use the Ethereum network, users must pay gas fees to compensate miners. These fees can range from a few dollars to several tens of dollars, and during periods of extreme network congestion, they have skyrocketed to hundreds of dollars per transaction. These high costs have driven some projects and users to seek alternatives on competing blockchains like Solana and Near.
To tackle these pressing issues, the Ethereum developer community has crafted a detailed roadmap for its evolution.
The Ethereum Upgrade Roadmap
The upgrade path, often called the Ethereum 2.0 roadmap, primarily consists of three core components: the Beacon Chain, The Merge, and Sharding. The first two steps focus on transitioning the network's consensus mechanism from PoW to Proof-of-Stake (PoS). The final step, sharding, is designed to dramatically improve the network's performance and scalability.
The Beacon Chain: Laying the PoS Foundation
To ensure a smooth transition to a new consensus mechanism, Ethereum launched a parallel blockchain on December 1, 2020, known as the Beacon Chain. This chain operates independently of the main Ethereum network using a pure PoS model.
Participants who wish to help secure the network must stake 32 ETH into a smart contract on the Beacon Chain. After a review process, they are added to a list of validators. These validators replace the role of miners; they are responsible for proposing and attesting to new blocks.
In a PoS system, the next block proposer is chosen algorithmically with a random element, ensuring the process remains decentralized. Validators are incentivized to act honestly; they earn rewards for good behavior but face penalties, including the loss of a portion of their staked ETH, for恶意行为 (malicious behavior). If a validator's stake falls below 16 ETH, they are removed from the validator set.
This current period, where the PoW mainnet and the PoS Beacon Chain run in parallel, is a preparatory phase. It allows the new PoS system to be thoroughly tested and to accumulate a significant amount of staked ETH to secure the network before the two chains become one.
The Merge: Unifying the Chains
The Merge refers to the historic event where the existing Ethereum Mainnet (the execution layer that handles transactions and smart contracts) merged with the Beacon Chain (the consensus layer). This event marked the end of Proof-of-Work for Ethereum.
Before executing The Merge on the main network, it was rigorously tested on several testnets. The Ropsten, Sepolia, and Goerli testnets all successfully underwent their own merges, serving as critical dress rehearsals.
A key mechanism to ensure the success of The Merge was the "Difficulty Bomb." This was code embedded in Ethereum years ago that gradually increases the difficulty of PoW mining over time. The purpose was to make mining progressively more challenging and less profitable, effectively encouraging miners to transition away from PoW and ensuring a smooth shift to PoS.
Sharding: The Scalability Solution
While the shift to PoS significantly reduces energy consumption, it does not, by itself, increase network capacity or transaction speed. Sharding is the upgrade designed to solve Ethereum's scalability issues.
Sharding is a concept borrowed from database architecture. It involves horizontally partitioning a database to spread the load. In Ethereum's context, the network will be split into smaller partitions called "shards." Each shard processes its own transactions and data, allowing many transactions to be handled in parallel. This parallel processing power is the key to unlocking higher throughput.
Ethereum's sharding plan has evolved. An initial proposal involved creating 64 new shard chains. However, with the rapid rise and success of Layer 2 scaling solutions, particularly Rollups, the plan was refined.
The new vision is a "rollup-centric roadmap." Instead of forcing the main Ethereum chain to handle all transactions, it will serve as a robust foundation for data availability and settlement. 👉 Explore more strategies for scalable blockchain solutions
In this model, Layer 2 rollups (like Optimistic Rollups and ZK-Rollups) execute thousands of transactions off-chain, bundle them together, and post compressed data and a cryptographic proof back to the main Ethereum chain. Ethereum's sharding upgrade will focus on providing abundant and cheap data storage space for these rollups, enabling them to offer users high throughput and very low fees.
The Impact of Ethereum's Upgrades
A Drastic Reduction in Energy Use
The transition to Proof-of-Stake is a monumental achievement for sustainability. By eliminating energy-intensive mining, Ethereum's energy consumption dropped by an estimated 99.95% overnight. The network's environmental footprint is now negligible compared to its PoW era.
Changes to ETH Issuance
With PoW mining retired, new ETH is no longer issued as block rewards to miners. Instead, new ETH is issued as rewards to validators who stake their coins to secure the network. This change has reduced the rate of new ETH issuance by approximately 90%. This event has been likened to three Bitcoin halvings happening at once. The significantly reduced issuance, combined with fees being burned, has led to periods of deflation, meaning the total supply of ETH has begun to decrease.
The Growth of ETH Staking
Post-Merge, staking ETH became the primary way to participate in network security and earn rewards. The annual yield for staking is typically in the single-digit percentage range, offering a relatively low-risk return. This has encouraged a significant portion of the ETH supply to be locked in the staking contract.
The complexity of running a validator node (requiring 32 ETH and technical know-how) has spurred the growth of staking services. These services allow users to stake any amount of ETH without managing hardware.
The Future for Miners
The Merge rendered Ethereum's PoW mining obsolete. The large community of ETH miners had to make a choice: repurpose their hardware to mine other PoW cryptocurrencies like Ethereum Classic (ETC) or shut down operations. While ETC can be mined with the same equipment, its lower economic value and smaller network cannot absorb all of Ethereum's former hash rate, leading to increased competition and lower profitability for miners in that space.
Frequently Asked Questions
What is the difference between Ethereum 1.0 and 2.0?
Ethereum 1.0 referred to the original Proof-of-Work blockchain. The term Ethereum 2.0 was used to describe the suite of upgrades, most notably the transition to Proof-of-Stake. The official terminology has been updated; what was called Eth2 is now the "consensus layer," and Eth1 is the "execution layer." They are now one unified chain.
How does staking on Ethereum work?
Staking involves depositing 32 ETH to activate validator software. As a validator, you are responsible for storing data, processing transactions, and adding new blocks to the blockchain. You earn rewards for this work but can also be penalized if your node goes offline or slashed for malicious actions.
Did The Merge reduce gas fees?
No, The Merge itself was a change of consensus mechanism, not a scalability upgrade. It did not lower gas fees. The primary solution for reducing gas fees is the continued adoption and improvement of Layer 2 scaling solutions like Rollups.
What are the risks of staking ETH?
The main risks are slashing (losing a portion of staked ETH due to malicious or careless behavior) and potential volatility in the price of ETH itself. Using a reputable staking service can help mitigate technical risks.
What is a Layer 2 rollup?
A Layer 2 is a separate blockchain that extends Ethereum. A rollup is a specific type of L2 that executes transactions outside of Ethereum Mainnet but posts transaction data back to Mainnet, inheriting its security. The two main types are Optimistic Rollups and Zero-Knowledge (ZK) Rollups.
When will sharding be implemented?
With the shift to a rollup-centric scaling plan, the focus of sharding has changed. The next major upgrade, often referred to as "Danksharding," will focus on providing massive data storage space for rollups. Its development is ongoing, with implementation expected in the coming years.
Conclusion
Ethereum's journey through its major upgrades represents one of the most significant undertakings in the history of blockchain. The successful execution of The Merge marked a pivotal moment, drastically reducing the network's environmental impact and setting the stage for a sustainable future.
While the path forward continues to evolve, the core mission remains: to scale the network securely and decentralizedly. The focus has now shifted to supporting Layer 2 solutions that will provide the high throughput and low costs needed for mass adoption. The evolution of Ethereum is a continuous process, and the community eagerly anticipates the next chapters of innovation and growth.